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MontaukOS/programs/lib/libc/libc.c
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/*
* libc.c
* Minimal C standard library for MontaukOS userspace programs
* Based on the proven libc from the DOOM port.
* Copyright (c) 2025-2026 Daniel Hammer
*/
#include <stddef.h>
#include <stdint.h>
#include <stdarg.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <fcntl.h>
#include <sys/stat.h>
/* ========================================================================
Raw syscall wrappers (C versions matching kernel ABI)
======================================================================== */
static inline long _zos_syscall0(long nr) {
long ret;
__asm__ volatile("syscall" : "=a"(ret) : "a"(nr)
: "rcx", "r11", "rdi", "rsi", "rdx", "r8", "r9", "r10", "memory");
return ret;
}
static inline long _zos_syscall1(long nr, long a1) {
long ret;
__asm__ volatile(
"mov %[a1], %%rdi\n\t"
"syscall"
: "=a"(ret)
: "a"(nr), [a1] "r"(a1)
: "rcx", "r11", "rdi", "rsi", "rdx", "r8", "r9", "r10", "memory");
return ret;
}
static inline long _zos_syscall2(long nr, long a1, long a2) {
long ret;
__asm__ volatile(
"mov %[a1], %%rdi\n\t"
"mov %[a2], %%rsi\n\t"
"syscall"
: "=a"(ret)
: "a"(nr), [a1] "r"(a1), [a2] "r"(a2)
: "rcx", "r11", "rdi", "rsi", "rdx", "r8", "r9", "r10", "memory");
return ret;
}
static inline long _zos_syscall3(long nr, long a1, long a2, long a3) {
long ret;
__asm__ volatile(
"mov %[a1], %%rdi\n\t"
"mov %[a2], %%rsi\n\t"
"mov %[a3], %%rdx\n\t"
"syscall"
: "=a"(ret)
: "a"(nr), [a1] "r"(a1), [a2] "r"(a2), [a3] "r"(a3)
: "rcx", "r11", "rdi", "rsi", "rdx", "r8", "r9", "r10", "memory");
return ret;
}
static inline long _zos_syscall4(long nr, long a1, long a2, long a3, long a4) {
long ret;
__asm__ volatile(
"mov %[a1], %%rdi\n\t"
"mov %[a2], %%rsi\n\t"
"mov %[a3], %%rdx\n\t"
"mov %[a4], %%r10\n\t"
"syscall"
: "=a"(ret)
: "a"(nr), [a1] "r"(a1), [a2] "r"(a2), [a3] "r"(a3), [a4] "r"(a4)
: "rcx", "r11", "rdi", "rsi", "rdx", "r8", "r9", "r10", "memory");
return ret;
}
/* Syscall numbers */
#define SYS_EXIT 0
#define SYS_PRINT 4
#define SYS_PUTCHAR 5
#define SYS_OPEN 6
#define SYS_READ 7
#define SYS_GETSIZE 8
#define SYS_CLOSE 9
#define SYS_READDIR 10
#define SYS_ALLOC 11
#define SYS_FREE 12
#define SYS_GETCHAR 18
#define SYS_SPAWN 20
#define SYS_WAITPID 23
#define SYS_GETARGS 25
#define SYS_FWRITE 41
#define SYS_FCREATE 42
#define SYS_FDELETE 77
#define SYS_FMKDIR 78
/* ========================================================================
errno
======================================================================== */
int errno = 0;
/* ========================================================================
string.h functions
======================================================================== */
void *memcpy(void *dest, const void *src, size_t n) {
unsigned char *d = (unsigned char *)dest;
const unsigned char *s = (const unsigned char *)src;
/* Byte copy until 8-byte aligned */
while (n && ((uint64_t)d & 7)) { *d++ = *s++; n--; }
/* Bulk 8-byte copy */
uint64_t *d8 = (uint64_t *)d;
const uint64_t *s8 = (const uint64_t *)s;
size_t words = n / 8;
for (size_t i = 0; i < words; i++) d8[i] = s8[i];
/* Remainder */
d = (unsigned char *)(d8 + words);
s = (const unsigned char *)(s8 + words);
for (size_t i = 0; i < (n & 7); i++) d[i] = s[i];
return dest;
}
void *memset(void *s, int c, size_t n) {
unsigned char *p = (unsigned char *)s;
unsigned char v = (unsigned char)c;
/* Byte fill until 8-byte aligned */
while (n && ((uint64_t)p & 7)) { *p++ = v; n--; }
/* Bulk 8-byte fill */
uint64_t v8 = v;
v8 |= v8 << 8; v8 |= v8 << 16; v8 |= v8 << 32;
uint64_t *p8 = (uint64_t *)p;
size_t words = n / 8;
for (size_t i = 0; i < words; i++) p8[i] = v8;
/* Remainder */
p = (unsigned char *)(p8 + words);
for (size_t i = 0; i < (n & 7); i++) p[i] = v;
return s;
}
void *memmove(void *dest, const void *src, size_t n) {
unsigned char *d = (unsigned char *)dest;
const unsigned char *s = (const unsigned char *)src;
if (d < s || d >= s + n) {
memcpy(dest, src, n);
} else {
/* Backward copy — bulk 8 bytes at a time from end */
d += n; s += n;
while (n && ((uint64_t)d & 7)) { *--d = *--s; n--; }
uint64_t *d8 = (uint64_t *)d;
const uint64_t *s8 = (const uint64_t *)s;
size_t words = n / 8;
for (size_t i = 1; i <= words; i++) d8[-(long)i] = s8[-(long)i];
d = (unsigned char *)(d8 - words);
s = (const unsigned char *)(s8 - words);
for (size_t i = 1; i <= (n & 7); i++) d[-(long)i] = s[-(long)i];
}
return dest;
}
int memcmp(const void *s1, const void *s2, size_t n) {
const unsigned char *a = (const unsigned char *)s1;
const unsigned char *b = (const unsigned char *)s2;
for (size_t i = 0; i < n; i++) {
if (a[i] != b[i])
return a[i] < b[i] ? -1 : 1;
}
return 0;
}
void *memchr(const void *s, int c, size_t n) {
const unsigned char *p = (const unsigned char *)s;
unsigned char uc = (unsigned char)c;
for (size_t i = 0; i < n; i++) {
if (p[i] == uc)
return (void *)(p + i);
}
return (void *)0;
}
size_t strlen(const char *s) {
size_t len = 0;
while (s[len]) len++;
return len;
}
int strcmp(const char *a, const char *b) {
while (*a && *a == *b) { a++; b++; }
return (unsigned char)*a - (unsigned char)*b;
}
int strncmp(const char *a, const char *b, size_t n) {
for (size_t i = 0; i < n; i++) {
if (a[i] != b[i] || a[i] == 0)
return (unsigned char)a[i] - (unsigned char)b[i];
}
return 0;
}
char *strcpy(char *dest, const char *src) {
char *d = dest;
while ((*d++ = *src++));
return dest;
}
char *strncpy(char *dest, const char *src, size_t n) {
size_t i;
for (i = 0; i < n && src[i]; i++)
dest[i] = src[i];
for (; i < n; i++)
dest[i] = '\0';
return dest;
}
char *strcat(char *dest, const char *src) {
char *d = dest + strlen(dest);
while ((*d++ = *src++));
return dest;
}
char *strncat(char *dest, const char *src, size_t n) {
char *d = dest + strlen(dest);
size_t i;
for (i = 0; i < n && src[i]; i++)
d[i] = src[i];
d[i] = '\0';
return dest;
}
char *strchr(const char *s, int c) {
while (*s) {
if (*s == (char)c) return (char *)s;
s++;
}
return (c == 0) ? (char *)s : NULL;
}
char *strrchr(const char *s, int c) {
const char *last = NULL;
while (*s) {
if (*s == (char)c) last = s;
s++;
}
if (c == 0) return (char *)s;
return (char *)last;
}
int strcasecmp(const char *a, const char *b) {
while (*a && ((*a >= 'A' && *a <= 'Z') ? *a + 32 : *a) ==
((*b >= 'A' && *b <= 'Z') ? *b + 32 : *b)) { a++; b++; }
int ca = (*a >= 'A' && *a <= 'Z') ? *a + 32 : *a;
int cb = (*b >= 'A' && *b <= 'Z') ? *b + 32 : *b;
return ca - cb;
}
int strncasecmp(const char *a, const char *b, size_t n) {
for (size_t i = 0; i < n; i++) {
int ca = (a[i] >= 'A' && a[i] <= 'Z') ? a[i] + 32 : a[i];
int cb = (b[i] >= 'A' && b[i] <= 'Z') ? b[i] + 32 : b[i];
if (ca != cb || ca == 0) return ca - cb;
}
return 0;
}
char *strstr(const char *haystack, const char *needle) {
if (!*needle) return (char *)haystack;
size_t nlen = strlen(needle);
while (*haystack) {
if (strncmp(haystack, needle, nlen) == 0)
return (char *)haystack;
haystack++;
}
return NULL;
}
/* Forward declaration for strdup */
void *malloc(size_t size);
char *strdup(const char *s) {
size_t len = strlen(s) + 1;
char *d = (char *)malloc(len);
if (d) memcpy(d, s, len);
return d;
}
/* ========================================================================
ctype.h functions
======================================================================== */
int isalpha(int c) { return (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z'); }
int isdigit(int c) { return c >= '0' && c <= '9'; }
int isalnum(int c) { return isalpha(c) || isdigit(c); }
int isspace(int c) { return c == ' ' || c == '\t' || c == '\n' || c == '\r' || c == '\f' || c == '\v'; }
int isupper(int c) { return c >= 'A' && c <= 'Z'; }
int islower(int c) { return c >= 'a' && c <= 'z'; }
int isprint(int c) { return c >= 0x20 && c <= 0x7E; }
int ispunct(int c) { return isprint(c) && !isalnum(c) && c != ' '; }
int isxdigit(int c) { return isdigit(c) || (c >= 'a' && c <= 'f') || (c >= 'A' && c <= 'F'); }
int iscntrl(int c) { return (c >= 0 && c < 0x20) || c == 0x7F; }
int isgraph(int c) { return c > 0x20 && c <= 0x7E; }
int toupper(int c) { return (c >= 'a' && c <= 'z') ? c - 32 : c; }
int tolower(int c) { return (c >= 'A' && c <= 'Z') ? c + 32 : c; }
/* ========================================================================
Heap allocator (free-list, backed by SYS_ALLOC)
======================================================================== */
#define HEAP_MAGIC 0x5A484541ULL /* "ZHEA" */
#define FREED_MAGIC 0xDEADFEEEULL
struct HeapHeader {
uint64_t magic;
uint64_t size;
} __attribute__((packed));
struct FreeNode {
uint64_t size;
struct FreeNode *next;
};
/* Segregated free lists: power-of-2 size classes for blocks <= 4096 bytes */
#define NUM_BUCKETS 8
static const uint64_t BUCKET_SIZES[NUM_BUCKETS] = {
32, 64, 128, 256, 512, 1024, 2048, 4096
};
static struct FreeNode *g_buckets[NUM_BUCKETS] = {};
static struct FreeNode g_overflow = { 0, NULL };
static int g_heapInit = 0;
static int heap_bucket_index(uint64_t blockSize) {
if (blockSize <= 32) return 0;
if (blockSize <= 64) return 1;
if (blockSize <= 128) return 2;
if (blockSize <= 256) return 3;
if (blockSize <= 512) return 4;
if (blockSize <= 1024) return 5;
if (blockSize <= 2048) return 6;
if (blockSize <= 4096) return 7;
return -1;
}
/* Insert into overflow list (sorted by address, with coalescing) */
static void heap_insert_overflow(void *ptr, uint64_t size) {
struct FreeNode *node = (struct FreeNode *)ptr;
node->size = size;
struct FreeNode *prev = &g_overflow;
struct FreeNode *cur = g_overflow.next;
while (cur != NULL && cur < node) {
prev = cur;
cur = cur->next;
}
int merged_prev = 0;
if (prev != &g_overflow &&
(uint8_t *)prev + prev->size == (uint8_t *)node) {
prev->size += size;
node = prev;
merged_prev = 1;
}
if (cur != NULL &&
(uint8_t *)node + node->size == (uint8_t *)cur) {
node->size += cur->size;
node->next = cur->next;
if (!merged_prev) prev->next = node;
} else if (!merged_prev) {
node->next = cur;
prev->next = node;
}
}
/* Take a block >= needed from overflow. Splits remainder back. */
static void *heap_take_overflow(uint64_t needed) {
struct FreeNode *prev = &g_overflow;
struct FreeNode *cur = g_overflow.next;
while (cur != NULL) {
if (cur->size >= needed) {
uint64_t blockSize = cur->size;
prev->next = cur->next;
if (blockSize > needed + sizeof(struct FreeNode) + 16) {
heap_insert_overflow((uint8_t *)cur + needed, blockSize - needed);
}
return (void *)cur;
}
prev = cur;
cur = cur->next;
}
return NULL;
}
static void heap_grow(uint64_t bytes) {
uint64_t pages = (bytes + 0xFFF) / 0x1000;
if (pages < 4) pages = 4;
void *mem = (void *)_zos_syscall1(SYS_ALLOC, (long)(pages * 0x1000));
if (mem != NULL)
heap_insert_overflow(mem, pages * 0x1000);
}
/* Refill a small-block bucket from overflow */
static int heap_refill_bucket(int idx) {
uint64_t bsize = BUCKET_SIZES[idx];
uint64_t chunk = (bsize < 4096) ? 4096 : bsize;
void *block = heap_take_overflow(chunk);
if (block == NULL) {
heap_grow(chunk);
block = heap_take_overflow(chunk);
if (block == NULL) return 0;
}
uint64_t count = chunk / bsize;
for (uint64_t i = 0; i < count; i++) {
struct FreeNode *node = (struct FreeNode *)((uint8_t *)block + i * bsize);
node->size = bsize;
node->next = g_buckets[idx];
g_buckets[idx] = node;
}
return 1;
}
void *malloc(size_t size) {
if (!g_heapInit) {
heap_grow(16 * 0x1000);
g_heapInit = 1;
}
/* Guard against overflow: size + Header must not wrap */
if (size > (uint64_t)-1 - sizeof(struct HeapHeader) - 15)
return NULL;
uint64_t needed = size + sizeof(struct HeapHeader);
needed = (needed + 15) & ~15ULL;
int idx = heap_bucket_index(needed);
if (idx >= 0) {
/* Small allocation — use segregated bucket (O(1)) */
if (g_buckets[idx] == NULL && !heap_refill_bucket(idx))
return NULL;
struct FreeNode *node = g_buckets[idx];
g_buckets[idx] = node->next;
struct HeapHeader *hdr = (struct HeapHeader *)node;
hdr->magic = HEAP_MAGIC;
hdr->size = size;
return (void *)((uint8_t *)hdr + sizeof(struct HeapHeader));
}
/* Large allocation — search overflow list */
void *block = heap_take_overflow(needed);
if (block == NULL) {
heap_grow(needed);
block = heap_take_overflow(needed);
if (block == NULL) return NULL;
}
struct HeapHeader *hdr = (struct HeapHeader *)block;
hdr->magic = HEAP_MAGIC;
hdr->size = size;
return (void *)((uint8_t *)hdr + sizeof(struct HeapHeader));
}
void free(void *ptr) {
if (ptr == NULL) return;
struct HeapHeader *hdr = (struct HeapHeader *)((uint8_t *)ptr - sizeof(struct HeapHeader));
if (hdr->magic == FREED_MAGIC) return; /* double-free */
if (hdr->magic != HEAP_MAGIC) return; /* corrupt */
hdr->magic = FREED_MAGIC;
uint64_t blockSize = hdr->size + sizeof(struct HeapHeader);
blockSize = (blockSize + 15) & ~15ULL;
int idx = heap_bucket_index(blockSize);
if (idx >= 0) {
/* Small block — push onto bucket (O(1)) */
struct FreeNode *node = (struct FreeNode *)hdr;
node->size = BUCKET_SIZES[idx];
node->next = g_buckets[idx];
g_buckets[idx] = node;
} else {
/* Large block — sorted insert with coalescing */
heap_insert_overflow((void *)hdr, blockSize);
}
}
void *calloc(size_t nmemb, size_t size) {
/* Check for multiplication overflow */
if (nmemb != 0 && size > (size_t)-1 / nmemb)
return NULL;
size_t total = nmemb * size;
void *p = malloc(total);
if (p) memset(p, 0, total);
return p;
}
void *realloc(void *ptr, size_t size) {
if (ptr == NULL) return malloc(size);
if (size == 0) { free(ptr); return NULL; }
struct HeapHeader *hdr = (struct HeapHeader *)((uint8_t *)ptr - sizeof(struct HeapHeader));
uint64_t old = hdr->size;
/* Compute actual block size (accounting for bucket rounding) */
uint64_t oldBlock = (old + sizeof(struct HeapHeader) + 15) & ~15ULL;
int idx = heap_bucket_index(oldBlock);
if (idx >= 0) oldBlock = BUCKET_SIZES[idx];
uint64_t newNeed = (size + sizeof(struct HeapHeader) + 15) & ~15ULL;
if (newNeed <= oldBlock) {
hdr->size = size;
return ptr;
}
void *newp = malloc(size);
if (newp == NULL) return NULL;
size_t copySize = old < size ? old : size;
memcpy(newp, ptr, copySize);
free(ptr);
return newp;
}
/* ========================================================================
stdlib.h functions
======================================================================== */
int abs(int x) { return x < 0 ? -x : x; }
long labs(long x) { return x < 0 ? -x : x; }
int atoi(const char *s) {
int neg = 0, val = 0;
while (isspace((unsigned char)*s)) s++;
if (*s == '-') { neg = 1; s++; }
else if (*s == '+') { s++; }
while (isdigit((unsigned char)*s)) {
val = val * 10 + (*s - '0');
s++;
}
return neg ? -val : val;
}
long strtol(const char *nptr, char **endptr, int base) {
const char *s = nptr;
long val = 0;
int neg = 0;
while (isspace((unsigned char)*s)) s++;
if (*s == '-') { neg = 1; s++; }
else if (*s == '+') { s++; }
if (base == 0) {
if (*s == '0' && (s[1] == 'x' || s[1] == 'X')) { base = 16; s += 2; }
else if (*s == '0') { base = 8; s++; }
else base = 10;
} else if (base == 16 && *s == '0' && (s[1] == 'x' || s[1] == 'X')) {
s += 2;
}
while (*s) {
int digit;
if (*s >= '0' && *s <= '9') digit = *s - '0';
else if (*s >= 'a' && *s <= 'z') digit = *s - 'a' + 10;
else if (*s >= 'A' && *s <= 'Z') digit = *s - 'A' + 10;
else break;
if (digit >= base) break;
val = val * base + digit;
s++;
}
if (endptr) *endptr = (char *)s;
return neg ? -val : val;
}
unsigned long strtoul(const char *nptr, char **endptr, int base) {
const char *s = nptr;
unsigned long val = 0;
while (isspace((unsigned char)*s)) s++;
/* strtoul allows an optional leading + or - (result is negated for -) */
int neg = 0;
if (*s == '-') { neg = 1; s++; }
else if (*s == '+') { s++; }
if (base == 0) {
if (*s == '0' && (s[1] == 'x' || s[1] == 'X')) { base = 16; s += 2; }
else if (*s == '0') { base = 8; s++; }
else base = 10;
} else if (base == 16 && *s == '0' && (s[1] == 'x' || s[1] == 'X')) {
s += 2;
}
while (*s) {
int digit;
if (*s >= '0' && *s <= '9') digit = *s - '0';
else if (*s >= 'a' && *s <= 'z') digit = *s - 'a' + 10;
else if (*s >= 'A' && *s <= 'Z') digit = *s - 'A' + 10;
else break;
if (digit >= base) break;
val = val * (unsigned long)base + (unsigned long)digit;
s++;
}
if (endptr) *endptr = (char *)s;
return neg ? (unsigned long)(-(long)val) : val;
}
char *getenv(const char *name) {
(void)name;
return NULL;
}
static void (*_atexit_funcs[32])(void);
static int _atexit_count = 0;
int atexit(void (*func)(void)) {
if (_atexit_count >= 32 || func == NULL) return -1;
_atexit_funcs[_atexit_count++] = func;
return 0;
}
void exit(int status) {
for (int i = _atexit_count - 1; i >= 0; i--)
_atexit_funcs[i]();
_zos_syscall1(SYS_EXIT, (long)status);
__builtin_unreachable();
}
void abort(void) {
_zos_syscall1(SYS_PRINT, (long)"abort() called\n");
_zos_syscall1(SYS_EXIT, 1);
__builtin_unreachable();
}
int system(const char *command) {
if (command == NULL) return -1;
int pid = (int)_zos_syscall2(SYS_SPAWN, (long)command, 0L);
if (pid < 0) return -1;
_zos_syscall1(SYS_WAITPID, (long)pid);
return 0;
}
/* ========================================================================
printf family — vsnprintf core
======================================================================== */
struct _pf_state {
char *buf;
size_t pos;
size_t max;
};
static void _pf_putc(struct _pf_state *st, char c) {
if (st->pos < st->max)
st->buf[st->pos] = c;
st->pos++;
}
static void _pf_puts(struct _pf_state *st, const char *s) {
while (*s) _pf_putc(st, *s++);
}
static void _pf_putnum(struct _pf_state *st, unsigned long val, int base, int upper, int width, char pad, int neg, int precision) {
char tmp[24];
int i = 0;
const char *digits = upper ? "0123456789ABCDEF" : "0123456789abcdef";
if (val == 0) {
tmp[i++] = '0';
} else {
while (val > 0) {
tmp[i++] = digits[val % base];
val /= base;
}
}
int digitCount = i;
int precPad = 0;
if (precision > digitCount)
precPad = precision - digitCount;
int total = (neg ? 1 : 0) + precPad + digitCount;
if (neg && pad == '0' && precision < 0) {
_pf_putc(st, '-');
}
if (precision < 0 && pad == '0') {
for (int w = total; w < width; w++)
_pf_putc(st, '0');
} else {
for (int w = total; w < width; w++)
_pf_putc(st, ' ');
}
if (neg && !(pad == '0' && precision < 0)) {
_pf_putc(st, '-');
}
for (int p = 0; p < precPad; p++)
_pf_putc(st, '0');
while (i > 0)
_pf_putc(st, tmp[--i]);
}
int vsnprintf(char *buf, size_t size, const char *fmt, va_list ap) {
struct _pf_state st;
st.buf = buf;
st.pos = 0;
st.max = size > 0 ? size - 1 : 0;
while (*fmt) {
if (*fmt != '%') {
_pf_putc(&st, *fmt++);
continue;
}
fmt++;
char pad = ' ';
int left_align = 0;
while (*fmt == '0' || *fmt == '-' || *fmt == '+' || *fmt == ' ') {
if (*fmt == '0') pad = '0';
if (*fmt == '-') { left_align = 1; pad = ' '; }
fmt++;
}
int width = 0;
if (*fmt == '*') {
width = va_arg(ap, int);
fmt++;
} else {
while (*fmt >= '0' && *fmt <= '9') {
width = width * 10 + (*fmt - '0');
fmt++;
}
}
int precision = -1;
if (*fmt == '.') {
fmt++;
precision = 0;
if (*fmt == '*') {
precision = va_arg(ap, int);
fmt++;
} else {
while (*fmt >= '0' && *fmt <= '9') {
precision = precision * 10 + (*fmt - '0');
fmt++;
}
}
}
int is_long = 0;
if (*fmt == 'l') { is_long = 1; fmt++; if (*fmt == 'l') { is_long = 2; fmt++; } }
else if (*fmt == 'h') { fmt++; if (*fmt == 'h') fmt++; }
else if (*fmt == 'z') { is_long = 1; fmt++; }
switch (*fmt) {
case 'd': case 'i': {
long val;
if (is_long >= 1) val = va_arg(ap, long);
else val = va_arg(ap, int);
int neg = 0;
unsigned long uval;
if (val < 0) { neg = 1; uval = (unsigned long)(-val); }
else uval = (unsigned long)val;
if (left_align) {
size_t before = st.pos;
_pf_putnum(&st, uval, 10, 0, 0, pad, neg, precision);
size_t len = st.pos - before;
for (size_t w = len; (int)w < width; w++) _pf_putc(&st, ' ');
} else {
_pf_putnum(&st, uval, 10, 0, width, pad, neg, precision);
}
break;
}
case 'u': {
unsigned long val;
if (is_long >= 1) val = va_arg(ap, unsigned long);
else val = va_arg(ap, unsigned int);
if (left_align) {
size_t before = st.pos;
_pf_putnum(&st, val, 10, 0, 0, ' ', 0, precision);
size_t len = st.pos - before;
for (size_t w = len; (int)w < width; w++) _pf_putc(&st, ' ');
} else {
_pf_putnum(&st, val, 10, 0, width, pad, 0, precision);
}
break;
}
case 'x': case 'X': {
unsigned long val;
if (is_long >= 1) val = va_arg(ap, unsigned long);
else val = va_arg(ap, unsigned int);
int upper = (*fmt == 'X');
if (left_align) {
size_t before = st.pos;
_pf_putnum(&st, val, 16, upper, 0, pad, 0, precision);
size_t len = st.pos - before;
for (size_t w = len; (int)w < width; w++) _pf_putc(&st, ' ');
} else {
_pf_putnum(&st, val, 16, upper, width, pad, 0, precision);
}
break;
}
case 'p': {
void *val = va_arg(ap, void *);
_pf_puts(&st, "0x");
_pf_putnum(&st, (unsigned long)val, 16, 0, 0, '0', 0, -1);
break;
}
case 's': {
const char *s = va_arg(ap, const char *);
if (s == NULL) s = "(null)";
int slen = (int)strlen(s);
if (precision >= 0 && precision < slen) slen = precision;
if (!left_align) {
for (int w = slen; w < width; w++) _pf_putc(&st, ' ');
}
for (int i = 0; i < slen; i++) _pf_putc(&st, s[i]);
if (left_align) {
for (int w = slen; w < width; w++) _pf_putc(&st, ' ');
}
break;
}
case 'c': {
char c = (char)va_arg(ap, int);
_pf_putc(&st, c);
break;
}
case '%':
_pf_putc(&st, '%');
break;
default:
_pf_putc(&st, '%');
_pf_putc(&st, *fmt);
break;
}
if (*fmt) fmt++;
}
if (size > 0) {
if (st.pos < size)
st.buf[st.pos] = '\0';
else
st.buf[size - 1] = '\0';
}
return (int)st.pos;
}
int snprintf(char *buf, size_t size, const char *fmt, ...) {
va_list ap;
va_start(ap, fmt);
int ret = vsnprintf(buf, size, fmt, ap);
va_end(ap);
return ret;
}
int sprintf(char *buf, const char *fmt, ...) {
va_list ap;
va_start(ap, fmt);
int ret = vsnprintf(buf, (size_t)-1, fmt, ap);
va_end(ap);
return ret;
}
static char _printbuf[4096];
int printf(const char *fmt, ...) {
va_list ap;
va_start(ap, fmt);
int ret = vsnprintf(_printbuf, sizeof(_printbuf), fmt, ap);
va_end(ap);
_zos_syscall1(SYS_PRINT, (long)_printbuf);
return ret;
}
int puts(const char *s) {
_zos_syscall1(SYS_PRINT, (long)s);
_zos_syscall1(SYS_PUTCHAR, (long)'\n');
return 0;
}
int putchar(int c) {
_zos_syscall1(SYS_PUTCHAR, (long)c);
return c;
}
/* ========================================================================
assert.h support
======================================================================== */
void __assert_fail(const char *expr, const char *file, int line, const char *func) {
_zos_syscall1(SYS_PRINT, (long)"Assertion failed: ");
_zos_syscall1(SYS_PRINT, (long)expr);
_zos_syscall1(SYS_PRINT, (long)" at ");
_zos_syscall1(SYS_PRINT, (long)file);
_zos_syscall1(SYS_PRINT, (long)"\n");
(void)line; (void)func;
abort();
}
/* ========================================================================
stdio.h FILE-based I/O
======================================================================== */
/* Static FILE objects for standard streams */
static FILE _stdin_file = { .handle = -1, .pos = 0, .size = 0, .eof = 0,
.error = 0, .is_std = 1, .ungetc_buf = -1 };
static FILE _stdout_file = { .handle = -1, .pos = 0, .size = 0, .eof = 0,
.error = 0, .is_std = 2, .ungetc_buf = -1 };
static FILE _stderr_file = { .handle = -1, .pos = 0, .size = 0, .eof = 0,
.error = 0, .is_std = 3, .ungetc_buf = -1 };
FILE *stdin = &_stdin_file;
FILE *stdout = &_stdout_file;
FILE *stderr = &_stderr_file;
FILE *fopen(const char *path, const char *mode) {
if (path == NULL || mode == NULL) return NULL;
int handle = -1;
int want_read = 0;
int want_write = 0;
int want_append = 0;
if (mode[0] == 'r') {
want_read = 1;
if (mode[1] == '+') want_write = 1;
} else if (mode[0] == 'w') {
want_write = 1;
if (mode[1] == '+') want_read = 1;
/* Truncate: delete then create */
_zos_syscall1(SYS_FDELETE, (long)path);
handle = (int)_zos_syscall1(SYS_FCREATE, (long)path);
if (handle < 0) return NULL;
} else if (mode[0] == 'a') {
want_write = 1;
want_append = 1;
if (mode[1] == '+') want_read = 1;
/* Try open existing, create if not found */
handle = (int)_zos_syscall1(SYS_OPEN, (long)path);
if (handle < 0) {
handle = (int)_zos_syscall1(SYS_FCREATE, (long)path);
if (handle < 0) return NULL;
}
} else {
return NULL;
}
/* For read and read+ modes, just open existing */
if (mode[0] == 'r') {
handle = (int)_zos_syscall1(SYS_OPEN, (long)path);
if (handle < 0) return NULL;
}
unsigned long fileSize = (unsigned long)_zos_syscall1(SYS_GETSIZE, (long)handle);
FILE *f = (FILE *)malloc(sizeof(FILE));
if (f == NULL) {
_zos_syscall1(SYS_CLOSE, (long)handle);
return NULL;
}
f->handle = handle;
f->size = fileSize;
f->pos = want_append ? fileSize : 0;
f->eof = 0;
f->error = 0;
f->is_std = 0;
f->ungetc_buf = -1;
(void)want_read;
(void)want_write;
return f;
}
int fclose(FILE *stream) {
if (stream == NULL) return EOF;
if (stream->is_std) return 0;
_zos_syscall1(SYS_CLOSE, (long)stream->handle);
free(stream);
return 0;
}
size_t fread(void *ptr, size_t size, size_t nmemb, FILE *stream) {
if (stream == NULL || ptr == NULL || size == 0 || nmemb == 0) return 0;
if (stream->is_std == 1) {
/* stdin: read characters via SYS_GETCHAR */
size_t total = size * nmemb;
char *dst = (char *)ptr;
size_t i;
for (i = 0; i < total; i++) {
int c = (int)_zos_syscall0(SYS_GETCHAR);
if (c <= 0) { stream->eof = 1; break; }
dst[i] = (char)c;
}
return i / size;
}
size_t total = size * nmemb;
size_t remaining = (stream->pos < stream->size) ? stream->size - stream->pos : 0;
if (total > remaining) {
total = remaining;
stream->eof = 1;
}
if (total == 0) return 0;
int ret = (int)_zos_syscall4(SYS_READ, (long)stream->handle,
(long)ptr, (long)stream->pos, (long)total);
if (ret < 0) {
stream->error = 1;
return 0;
}
stream->pos += (unsigned long)ret;
return (size_t)ret / size;
}
size_t fwrite(const void *ptr, size_t size, size_t nmemb, FILE *stream) {
if (stream == NULL || ptr == NULL || size == 0 || nmemb == 0) return 0;
if (stream->is_std) {
/* stdout/stderr: print via SYS_PRINT/SYS_PUTCHAR */
size_t total = size * nmemb;
const char *src = (const char *)ptr;
for (size_t i = 0; i < total; i++)
_zos_syscall1(SYS_PUTCHAR, (long)(unsigned char)src[i]);
return nmemb;
}
size_t total = size * nmemb;
int ret = (int)_zos_syscall4(SYS_FWRITE, (long)stream->handle,
(long)ptr, (long)stream->pos, (long)total);
if (ret < 0) {
stream->error = 1;
return 0;
}
stream->pos += (unsigned long)ret;
/* Update size if we wrote past the old end */
if (stream->pos > stream->size)
stream->size = stream->pos;
return (size_t)ret / size;
}
int fseek(FILE *stream, long offset, int whence) {
if (stream == NULL || stream->is_std) return -1;
unsigned long newpos;
switch (whence) {
case SEEK_SET: newpos = (unsigned long)offset; break;
case SEEK_CUR: newpos = stream->pos + (unsigned long)offset; break;
case SEEK_END: newpos = stream->size + (unsigned long)offset; break;
default: return -1;
}
stream->pos = newpos;
stream->eof = 0;
return 0;
}
long ftell(FILE *stream) {
if (stream == NULL) return -1;
return (long)stream->pos;
}
int fflush(FILE *stream) {
/* No buffering in this implementation */
(void)stream;
return 0;
}
int feof(FILE *stream) {
if (stream == NULL) return 0;
return stream->eof;
}
int ferror(FILE *stream) {
if (stream == NULL) return 0;
return stream->error;
}
void clearerr(FILE *stream) {
if (stream == NULL) return;
stream->eof = 0;
stream->error = 0;
}
int fgetc(FILE *stream) {
if (stream == NULL) return EOF;
/* Check ungetc buffer first */
if (stream->ungetc_buf >= 0) {
int c = stream->ungetc_buf;
stream->ungetc_buf = -1;
return c;
}
if (stream->is_std == 1) {
int c = (int)_zos_syscall0(SYS_GETCHAR);
if (c <= 0) { stream->eof = 1; return EOF; }
return c;
}
if (stream->pos >= stream->size) {
stream->eof = 1;
return EOF;
}
unsigned char c;
int ret = (int)_zos_syscall4(SYS_READ, (long)stream->handle,
(long)&c, (long)stream->pos, 1L);
if (ret <= 0) {
stream->eof = 1;
return EOF;
}
stream->pos++;
return (int)c;
}
int getc(FILE *stream) {
return fgetc(stream);
}
int ungetc(int c, FILE *stream) {
if (stream == NULL || c == EOF) return EOF;
stream->ungetc_buf = c;
stream->eof = 0;
return c;
}
char *fgets(char *s, int size, FILE *stream) {
if (s == NULL || size <= 0 || stream == NULL) return NULL;
int i = 0;
while (i < size - 1) {
int c = fgetc(stream);
if (c == EOF) {
if (i == 0) return NULL;
break;
}
s[i++] = (char)c;
if (c == '\n') break;
}
s[i] = '\0';
return s;
}
int fputs(const char *s, FILE *stream) {
if (s == NULL || stream == NULL) return EOF;
size_t len = strlen(s);
size_t written = fwrite(s, 1, len, stream);
return (written == len) ? 0 : EOF;
}
int fprintf(FILE *stream, const char *fmt, ...) {
char buf[4096];
va_list ap;
va_start(ap, fmt);
int n = vsnprintf(buf, sizeof(buf), fmt, ap);
va_end(ap);
if (stream == NULL || stream->is_std) {
_zos_syscall1(SYS_PRINT, (long)buf);
} else {
fwrite(buf, 1, (size_t)(n > 0 ? n : 0), stream);
}
return n;
}
int vfprintf(FILE *stream, const char *fmt, va_list ap) {
char buf[4096];
int n = vsnprintf(buf, sizeof(buf), fmt, ap);
if (stream == NULL || stream->is_std) {
_zos_syscall1(SYS_PRINT, (long)buf);
} else {
fwrite(buf, 1, (size_t)(n > 0 ? n : 0), stream);
}
return n;
}
int vprintf(const char *fmt, va_list ap) {
return vfprintf(stdout, fmt, ap);
}
int vsprintf(char *str, const char *fmt, va_list ap) {
return vsnprintf(str, (size_t)-1, fmt, ap);
}
int remove(const char *path) {
if (path == NULL) return -1;
return (int)_zos_syscall1(SYS_FDELETE, (long)path);
}
int rename(const char *oldpath, const char *newpath) {
/* No atomic rename syscall -- copy + delete */
if (oldpath == NULL || newpath == NULL) return -1;
int src = (int)_zos_syscall1(SYS_OPEN, (long)oldpath);
if (src < 0) return -1;
unsigned long sz = (unsigned long)_zos_syscall1(SYS_GETSIZE, (long)src);
/* Create destination */
_zos_syscall1(SYS_FDELETE, (long)newpath);
int dst = (int)_zos_syscall1(SYS_FCREATE, (long)newpath);
if (dst < 0) {
_zos_syscall1(SYS_CLOSE, (long)src);
return -1;
}
/* Copy in chunks */
char copybuf[4096];
unsigned long off = 0;
while (off < sz) {
unsigned long chunk = sz - off;
if (chunk > sizeof(copybuf)) chunk = sizeof(copybuf);
int r = (int)_zos_syscall4(SYS_READ, (long)src,
(long)copybuf, (long)off, (long)chunk);
if (r <= 0) break;
_zos_syscall4(SYS_FWRITE, (long)dst,
(long)copybuf, (long)off, (long)r);
off += (unsigned long)r;
}
_zos_syscall1(SYS_CLOSE, (long)src);
_zos_syscall1(SYS_CLOSE, (long)dst);
_zos_syscall1(SYS_FDELETE, (long)oldpath);
return 0;
}
void perror(const char *s) {
if (s != NULL && s[0] != '\0') {
_zos_syscall1(SYS_PRINT, (long)s);
_zos_syscall1(SYS_PRINT, (long)": ");
}
_zos_syscall1(SYS_PRINT, (long)"error\n");
}
FILE *tmpfile(void) {
return NULL;
}
char *tmpnam(char *s) {
(void)s;
return NULL;
}
/* ========================================================================
sscanf (minimal: %d, %x, %s, %c, %u, %ld, %lu)
======================================================================== */
int sscanf(const char *str, const char *fmt, ...) {
va_list ap;
va_start(ap, fmt);
int matched = 0;
const char *s = str;
while (*fmt) {
if (*fmt == '%') {
fmt++;
int is_long = 0;
if (*fmt == 'l') { is_long = 1; fmt++; }
if (*fmt == 'd' || *fmt == 'i') {
while (isspace((unsigned char)*s)) s++;
int neg = 0;
if (*s == '-') { neg = 1; s++; }
else if (*s == '+') s++;
if (!isdigit((unsigned char)*s)) goto done;
long val = 0;
while (isdigit((unsigned char)*s))
val = val * 10 + (*s++ - '0');
if (neg) val = -val;
if (is_long) *va_arg(ap, long *) = val;
else *va_arg(ap, int *) = (int)val;
matched++;
} else if (*fmt == 'u') {
while (isspace((unsigned char)*s)) s++;
if (!isdigit((unsigned char)*s)) goto done;
unsigned long val = 0;
while (isdigit((unsigned char)*s))
val = val * 10 + (unsigned long)(*s++ - '0');
if (is_long) *va_arg(ap, unsigned long *) = val;
else *va_arg(ap, unsigned int *) = (unsigned int)val;
matched++;
} else if (*fmt == 'x' || *fmt == 'X') {
while (isspace((unsigned char)*s)) s++;
if (s[0] == '0' && (s[1] == 'x' || s[1] == 'X')) s += 2;
if (!isxdigit((unsigned char)*s)) goto done;
unsigned long val = 0;
while (isxdigit((unsigned char)*s)) {
int d;
if (*s >= '0' && *s <= '9') d = *s - '0';
else if (*s >= 'a' && *s <= 'f') d = *s - 'a' + 10;
else d = *s - 'A' + 10;
val = val * 16 + (unsigned long)d;
s++;
}
if (is_long) *va_arg(ap, unsigned long *) = val;
else *va_arg(ap, unsigned int *) = (unsigned int)val;
matched++;
} else if (*fmt == 's') {
while (isspace((unsigned char)*s)) s++;
char *dst = va_arg(ap, char *);
if (*s == '\0') goto done;
while (*s && !isspace((unsigned char)*s))
*dst++ = *s++;
*dst = '\0';
matched++;
} else if (*fmt == 'c') {
if (*s == '\0') goto done;
*va_arg(ap, char *) = *s++;
matched++;
} else if (*fmt == '%') {
if (*s != '%') goto done;
s++;
}
fmt++;
} else if (isspace((unsigned char)*fmt)) {
while (isspace((unsigned char)*s)) s++;
fmt++;
} else {
if (*s != *fmt) goto done;
s++;
fmt++;
}
}
done:
va_end(ap);
return matched;
}
/* ========================================================================
fcntl.h / unistd.h POSIX-style file I/O
======================================================================== */
/* fd position tracking for POSIX read/write (MontaukOS uses explicit offsets) */
#define _FD_POS_MAX 64
static unsigned long _fd_pos[_FD_POS_MAX];
int open(const char *path, int flags, ...) {
if (path == NULL) return -1;
int h;
if (flags & 0x40 /* O_CREAT */) {
_zos_syscall1(SYS_FDELETE, (long)path);
h = (int)_zos_syscall1(SYS_FCREATE, (long)path);
} else {
h = (int)_zos_syscall1(SYS_OPEN, (long)path);
}
if (h >= 0 && h < _FD_POS_MAX)
_fd_pos[h] = 0;
return h;
}
int read(int fd, void *buf, size_t count) {
if (buf == NULL) return -1;
unsigned long pos = (fd >= 0 && fd < _FD_POS_MAX) ? _fd_pos[fd] : 0;
int ret = (int)_zos_syscall4(SYS_READ, (long)fd, (long)buf, (long)pos, (long)count);
if (ret > 0 && fd >= 0 && fd < _FD_POS_MAX)
_fd_pos[fd] += (unsigned long)ret;
return ret;
}
int write(int fd, const void *buf, size_t count) {
if (buf == NULL) return -1;
unsigned long pos = (fd >= 0 && fd < _FD_POS_MAX) ? _fd_pos[fd] : 0;
int ret = (int)_zos_syscall4(SYS_FWRITE, (long)fd, (long)buf, (long)pos, (long)count);
if (ret > 0 && fd >= 0 && fd < _FD_POS_MAX)
_fd_pos[fd] += (unsigned long)ret;
return ret;
}
int close(int fd) {
if (fd >= 0 && fd < _FD_POS_MAX)
_fd_pos[fd] = 0;
_zos_syscall1(SYS_CLOSE, (long)fd);
return 0;
}
long lseek(int fd, long offset, int whence) {
unsigned long pos = (fd >= 0 && fd < _FD_POS_MAX) ? _fd_pos[fd] : 0;
unsigned long newpos;
switch (whence) {
case 0: /* SEEK_SET */
newpos = (unsigned long)offset;
break;
case 1: /* SEEK_CUR */
newpos = pos + (unsigned long)offset;
break;
case 2: /* SEEK_END */
newpos = (unsigned long)_zos_syscall1(SYS_GETSIZE, (long)fd) + (unsigned long)offset;
break;
default:
return -1;
}
if (fd >= 0 && fd < _FD_POS_MAX)
_fd_pos[fd] = newpos;
return (long)newpos;
}
/* ========================================================================
sys/stat.h functions
======================================================================== */
int mkdir(const char *path, unsigned int mode) {
(void)mode;
if (path == NULL) return -1;
return (int)_zos_syscall1(SYS_FMKDIR, (long)path);
}
int stat(const char *path, struct stat *buf) {
if (path == NULL || buf == NULL) return -1;
int h = (int)_zos_syscall1(SYS_OPEN, (long)path);
if (h < 0) return -1;
buf->st_size = (unsigned long)_zos_syscall1(SYS_GETSIZE, (long)h);
_zos_syscall1(SYS_CLOSE, (long)h);
return 0;
}
int fstat(int fd, struct stat *buf) {
if (buf == NULL) return -1;
buf->st_size = (unsigned long)_zos_syscall1(SYS_GETSIZE, (long)fd);
return 0;
}
/* ========================================================================
stdlib.h: qsort
======================================================================== */
void qsort(void *base, size_t nmemb, size_t size,
int (*compar)(const void *, const void *)) {
if (nmemb < 2 || base == NULL || compar == NULL) return;
/* Simple insertion sort for small arrays, good enough for libc */
unsigned char *b = (unsigned char *)base;
unsigned char tmp[256];
int use_heap = (size > sizeof(tmp));
unsigned char *t = use_heap ? (unsigned char *)malloc(size) : tmp;
if (t == NULL) return;
for (size_t i = 1; i < nmemb; i++) {
unsigned char *cur = b + i * size;
size_t j = i;
while (j > 0) {
unsigned char *prev = b + (j - 1) * size;
if (compar(prev, cur) <= 0) break;
j--;
cur = prev;
}
if (j != i) {
unsigned char *dst = b + j * size;
unsigned char *src = b + i * size;
memcpy(t, src, size);
memmove(dst + size, dst, (i - j) * size);
memcpy(dst, t, size);
}
}
if (use_heap) free(t);
}
/* ========================================================================
stdlib.h: rand / srand
======================================================================== */
static unsigned int _rand_seed = 1;
int rand(void) {
_rand_seed = _rand_seed * 1103515245 + 12345;
return (int)((_rand_seed >> 16) & 0x7fff);
}
void srand(unsigned int seed) {
_rand_seed = seed;
}
div_t div(int numer, int denom) {
div_t r;
r.quot = numer / denom;
r.rem = numer % denom;
return r;
}
ldiv_t ldiv(long numer, long denom) {
ldiv_t r;
r.quot = numer / denom;
r.rem = numer % denom;
return r;
}
long atol(const char *s) {
return strtol(s, NULL, 10);
}
/* ========================================================================
math.h functions
======================================================================== */
/* Constants */
#define M_PI 3.14159265358979323846
#define M_PI_2 1.57079632679489661923
#define M_LN2 0.69314718055994530942
#define M_LOG2E 1.44269504088896340736
double fabs(double x) { return x < 0 ? -x : x; }
double floor(double x) {
double t = (double)(long long)x;
return (x < t) ? t - 1.0 : t;
}
double ceil(double x) {
double f = floor(x);
return (x > f) ? f + 1.0 : f;
}
double fmod(double x, double y) {
if (y == 0.0) return 0.0;
return x - (double)((long long)(x / y)) * y;
}
double sqrt(double x) {
if (x <= 0.0) return 0.0;
double guess = x;
for (int i = 0; i < 20; i++)
guess = (guess + x / guess) * 0.5;
return guess;
}
/* ---- sin / cos via range reduction + minimax polynomial ---- */
/* Reduce x to [-pi, pi] */
static double _reduce_angle(double x) {
/* Bring into [-2pi, 2pi] via fmod, then into [-pi, pi] */
x = fmod(x, 2.0 * M_PI);
if (x > M_PI) x -= 2.0 * M_PI;
else if (x < -M_PI) x += 2.0 * M_PI;
return x;
}
/* Core sin approximation for x in [-pi/2, pi/2].
Taylor series to degree 17 for < 1e-11 accuracy at the boundary. */
static double _sin_core(double x) {
double x2 = x * x;
return x * (1.0 + x2 * (-1.0/6.0 + x2 * (1.0/120.0 + x2 * (-1.0/5040.0
+ x2 * (1.0/362880.0 + x2 * (-1.0/39916800.0
+ x2 * (1.0/6227020800.0 + x2 * (-1.0/1307674368000.0))))))));
}
double sin(double x) {
x = _reduce_angle(x);
/* Reduce to [-pi/2, pi/2] using sin(pi - x) = sin(x) */
if (x > M_PI_2) x = M_PI - x;
else if (x < -M_PI_2) x = -M_PI - x;
return _sin_core(x);
}
double cos(double x) {
return sin(x + M_PI_2);
}
/* ---- log via exponent extraction + polynomial on [1, 2) ---- */
/* Union for double bit manipulation */
typedef union { double d; uint64_t u; } _dbl_bits;
double log(double x) {
if (x <= 0.0) return -HUGE_VAL;
if (x == 1.0) return 0.0;
/* Extract exponent and mantissa: x = m * 2^e, where m in [1, 2) */
_dbl_bits bits;
bits.d = x;
int e = (int)((bits.u >> 52) & 0x7FF) - 1023;
bits.u = (bits.u & 0x000FFFFFFFFFFFFFULL) | 0x3FF0000000000000ULL;
double m = bits.d;
/* log(x) = e * ln(2) + log(m), where m in [1, 2)
Use log(m) = log((1+f)/(1-f)) = 2*(f + f^3/3 + f^5/5 + ...) where f = (m-1)/(m+1) */
double f = (m - 1.0) / (m + 1.0);
double f2 = f * f;
double ln_m = 2.0 * f * (1.0 + f2 * (1.0/3.0 + f2 * (1.0/5.0 + f2 * (1.0/7.0
+ f2 * (1.0/9.0 + f2 * (1.0/11.0 + f2 * (1.0/13.0
+ f2 * (1.0/15.0 + f2 * (1.0/17.0)))))))));
return (double)e * M_LN2 + ln_m;
}
/* ---- exp via range reduction to [0, ln2) + polynomial ---- */
double exp(double x) {
if (x == 0.0) return 1.0;
if (x < -708.0) return 0.0;
if (x > 709.0) return HUGE_VAL;
/* Range reduction: exp(x) = 2^k * exp(r), where x = k*ln(2) + r, |r| <= ln(2)/2 */
double k_real = floor(x * M_LOG2E + 0.5);
int k = (int)k_real;
double r = x - k_real * M_LN2;
/* Pade-like polynomial for exp(r), |r| <= ~0.347:
1 + r + r^2/2 + r^3/6 + r^4/24 + r^5/120 + r^6/720 + r^7/5040 */
double exp_r = 1.0 + r * (1.0 + r * (1.0/2.0 + r * (1.0/6.0
+ r * (1.0/24.0 + r * (1.0/120.0 + r * (1.0/720.0 + r * (1.0/5040.0)))))));
/* Multiply by 2^k via bit manipulation */
_dbl_bits bits;
bits.d = exp_r;
bits.u += (uint64_t)k << 52;
return bits.d;
}
/* ---- pow via exp(exp * log(base)) ---- */
double pow(double base, double e) {
if (e == 0.0) return 1.0;
if (base == 0.0) return 0.0;
if (base == 1.0) return 1.0;
if (e == 1.0) return base;
/* Integer exponent fast path */
if (e == (double)(long long)e && fabs(e) < 64) {
long long ei = (long long)e;
int neg = 0;
if (ei < 0) { neg = 1; ei = -ei; }
double r = 1.0;
double b = base;
while (ei > 0) {
if (ei & 1) r *= b;
b *= b;
ei >>= 1;
}
return neg ? 1.0 / r : r;
}
/* General case */
if (base < 0.0) return 0.0; /* negative base with fractional exp is undefined (in reals) */
return exp(e * log(base));
}
double tan(double x) {
double c = cos(x);
if (c == 0.0) return (sin(x) > 0.0) ? HUGE_VAL : -HUGE_VAL;
return sin(x) / c;
}
double log2(double x) { return log(x) * M_LOG2E; }
double log10(double x) { return log(x) * 0.43429448190325182765; /* 1/ln(10) */ }
/* ---- atan / atan2 via polynomial approximation ---- */
/* Core atan for |x| <= ~0.414 (= tan(pi/8)).
Taylor series converges well in this small range. */
static double _atan_small(double x) {
double x2 = x * x;
return x * (1.0 + x2 * (-1.0/3.0 + x2 * (1.0/5.0 + x2 * (-1.0/7.0
+ x2 * (1.0/9.0 + x2 * (-1.0/11.0 + x2 * (1.0/13.0
+ x2 * (-1.0/15.0 + x2 * (1.0/17.0)))))))));
}
#define M_PI_4 0.78539816339744830962
/* atan for x >= 0, using range reduction:
- |x| <= tan(pi/8) ~ 0.4142: polynomial directly
- 0.4142 < |x| <= 1: atan(x) = pi/4 + atan((x-1)/(x+1))
- |x| > 1: atan(x) = pi/2 - atan(1/x) */
static double _atan_positive(double x) {
if (x <= 0.41421356237309504) {
return _atan_small(x);
} else if (x <= 1.0) {
return M_PI_4 + _atan_small((x - 1.0) / (x + 1.0));
} else {
return M_PI_2 - _atan_positive(1.0 / x);
}
}
double atan2(double y, double x) {
if (x == 0.0 && y == 0.0) return 0.0;
if (x == 0.0) return (y > 0.0) ? M_PI_2 : -M_PI_2;
if (y == 0.0) return (x > 0.0) ? 0.0 : M_PI;
double a = _atan_positive(fabs(y) / fabs(x));
/* Map to correct quadrant */
if (x < 0.0) a = M_PI - a;
if (y < 0.0) a = -a;
return a;
}
double atan(double x) {
if (x >= 0.0) return _atan_positive(x);
return -_atan_positive(-x);
}
double round(double x) { return floor(x + 0.5); }
/* ---- atof: basic floating-point string parser ---- */
double atof(const char *s) {
if (s == NULL) return 0.0;
while (isspace((unsigned char)*s)) s++;
int neg = 0;
if (*s == '-') { neg = 1; s++; }
else if (*s == '+') s++;
/* Integer part */
double val = 0.0;
while (isdigit((unsigned char)*s)) {
val = val * 10.0 + (*s - '0');
s++;
}
/* Fractional part */
if (*s == '.') {
s++;
double place = 0.1;
while (isdigit((unsigned char)*s)) {
val += (*s - '0') * place;
place *= 0.1;
s++;
}
}
/* Exponent part */
if (*s == 'e' || *s == 'E') {
s++;
int eneg = 0;
if (*s == '-') { eneg = 1; s++; }
else if (*s == '+') s++;
int ev = 0;
while (isdigit((unsigned char)*s)) {
ev = ev * 10 + (*s - '0');
s++;
}
double mul = 1.0;
while (ev-- > 0) mul *= 10.0;
if (eneg) val /= mul;
else val *= mul;
}
return neg ? -val : val;
}
float floorf(float x) { return (float)floor((double)x); }
float ceilf(float x) { return (float)ceil((double)x); }
float fabsf(float x) { return x < 0.0f ? -x : x; }
float sqrtf(float x) { return (float)sqrt((double)x); }
float sinf(float x) { return (float)sin((double)x); }
float cosf(float x) { return (float)cos((double)x); }
/* ========================================================================
unistd.h: sleep
======================================================================== */
unsigned int sleep(unsigned int seconds) {
(void)seconds;
return 0;
}
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