330 lines
13 KiB
C
330 lines
13 KiB
C
/* spl_syscall.c — built-in syscall implementations + registration
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*
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* All syscalls validate nargs, cast spl_val_t args to the expected C types,
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* execute, and return the result as spl_val_t.
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*
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* Simple syscalls use the SYSCALL_N macros; complex ones are written
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* manually but follow the same template.
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*/
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#include "spl_syscall.h"
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#include "spl_vm.h"
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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/* =================================================================
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* Macro templates
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*
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* Each SYSCALL_N macro:
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* 1. Validates nargs (prints error and returns -1 on mismatch)
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* 2. Casts args[n] from spl_val_t to the specified C type via
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* (type)(uintptr_t) — this handles both integer and pointer types
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* 3. Evaluates the expression and returns the result as spl_val_t
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* ================================================================= */
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#define CHECK_NARGS(fname, expected) \
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do { \
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if (nargs != (expected)) { \
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fprintf(stderr, fname ": expected " #expected " args, got %d\n", nargs); \
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return -1; \
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} \
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} while (0)
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#define SYSCALL_0(name, ret_expr) \
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static spl_val_t name(int nargs, spl_val_t *args) { \
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CHECK_NARGS(#name, 0); \
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(void)args; \
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return (spl_val_t)(uintptr_t)(ret_expr); \
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}
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#define SYSCALL_1(name, t1, ret_expr) \
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static spl_val_t name(int nargs, spl_val_t *args) { \
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CHECK_NARGS(#name, 1); \
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t1 a1 = (t1)(uintptr_t)args[0]; \
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return (spl_val_t)(uintptr_t)(ret_expr); \
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}
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#define SYSCALL_2(name, t1, t2, ret_expr) \
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static spl_val_t name(int nargs, spl_val_t *args) { \
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CHECK_NARGS(#name, 2); \
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t1 a1 = (t1)(uintptr_t)args[0]; \
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t2 a2 = (t2)(uintptr_t)args[1]; \
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return (spl_val_t)(uintptr_t)(ret_expr); \
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}
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#define SYSCALL_3(name, t1, t2, t3, ret_expr) \
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static spl_val_t name(int nargs, spl_val_t *args) { \
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CHECK_NARGS(#name, 3); \
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t1 a1 = (t1)(uintptr_t)args[0]; \
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t2 a2 = (t2)(uintptr_t)args[1]; \
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t3 a3 = (t3)(uintptr_t)args[2]; \
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return (spl_val_t)(uintptr_t)(ret_expr); \
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}
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#define SYSCALL_4(name, t1, t2, t3, t4, ret_expr) \
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static spl_val_t name(int nargs, spl_val_t *args) { \
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CHECK_NARGS(#name, 4); \
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t1 a1 = (t1)(uintptr_t)args[0]; \
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t2 a2 = (t2)(uintptr_t)args[1]; \
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t3 a3 = (t3)(uintptr_t)args[2]; \
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t4 a4 = (t4)(uintptr_t)args[3]; \
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return (spl_val_t)(uintptr_t)(ret_expr); \
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}
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/* =================================================================
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* OS syscalls
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* ================================================================= */
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/* os_exit — terminate process with the given exit code */
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SYSCALL_1(os_exit, int, (exit(a1), (spl_val_t)0))
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/* os_putchar — write a single character to stdout */
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SYSCALL_1(os_putchar, int, putchar(a1))
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/* os_getchar — read a single character from stdin */
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SYSCALL_0(os_getchar, getchar())
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/* os_putint — print an integer to stdout */
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SYSCALL_1(os_putint, int, (fprintf(stdout, "%d", a1), (spl_val_t)0))
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/* os_putstr — print a string to stdout (no trailing newline) */
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SYSCALL_1(os_putstr, const char *, (fputs(a1, stdout), (spl_val_t)0))
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/* os_fopen — open a file, returns FILE* as spl_val_t */
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SYSCALL_2(os_fopen, const char *, const char *, (uintptr_t)fopen(a1, a2))
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/* os_fclose — close a file, returns 0 on success */
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SYSCALL_1(os_fclose, FILE *, fclose(a1))
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/* os_fread — read from file, returns number of items read */
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SYSCALL_4(os_fread, void *, size_t, size_t, FILE *, fread(a1, a2, a3, a4))
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/* os_fwrite — write to file, returns number of items written */
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SYSCALL_4(os_fwrite, const void *, size_t, size_t, FILE *, fwrite(a1, a2, a3, a4))
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/* os_fsize — get file size in bytes */
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static spl_val_t os_fsize(int nargs, spl_val_t *args) {
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CHECK_NARGS("os_fsize", 1);
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FILE *f = (FILE *)(uintptr_t)args[0];
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long cur = ftell(f);
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fseek(f, 0, SEEK_END);
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long sz = ftell(f);
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fseek(f, cur, SEEK_SET);
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return (spl_val_t)(uintptr_t)sz;
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}
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/* os_read_file — read entire file into a malloc'd, null-terminated buffer */
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static spl_val_t os_read_file(int nargs, spl_val_t *args) {
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CHECK_NARGS("os_read_file", 1);
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const char *path = (const char *)(uintptr_t)args[0];
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FILE *f = fopen(path, "rb");
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if (!f)
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return 0;
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fseek(f, 0, SEEK_END);
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long sz = ftell(f);
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fseek(f, 0, SEEK_SET);
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char *buf = (char *)malloc((size_t)sz + 1);
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if (!buf) {
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fclose(f);
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return 0;
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}
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size_t nread = fread(buf, 1, (size_t)sz, f);
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fclose(f);
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buf[nread] = '\0';
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return (spl_val_t)(uintptr_t)buf;
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}
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/* os_alloc — allocate memory (malloc) */
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SYSCALL_1(os_alloc, size_t, (uintptr_t)malloc(a1))
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/* os_free — free memory */
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SYSCALL_1(os_free, void *, (free(a1), (spl_val_t)0))
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/* os_realloc — reallocate memory (realloc) */
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SYSCALL_2(os_realloc, void *, size_t, (uintptr_t)realloc(a1, a2))
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/* os_strlen — get string length */
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SYSCALL_1(os_strlen, const char *, strlen(a1))
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/* os_strcmp — compare two strings */
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SYSCALL_2(os_strcmp, const char *, const char *, strcmp(a1, a2))
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/* os_memcpy — copy memory, returns dst */
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SYSCALL_3(os_memcpy, void *, const void *, size_t, (memcpy(a1, a2, a3), (uintptr_t)a1))
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/* =================================================================
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* VM syscalls (for comptime — compile-time code execution)
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*
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* These let SPL code create isolated sub-VMs, load compiled .sir
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* programs into them, push arguments, call functions, and run.
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* ================================================================= */
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/* vm_new — create a new sub-VM instance, returns spl_vm_t* */
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static spl_val_t vm_new(int nargs, spl_val_t *args) {
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CHECK_NARGS("vm_new", 0);
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(void)args;
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spl_vm_t *vm = (spl_vm_t *)malloc(sizeof(spl_vm_t));
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if (!vm)
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return 0;
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spl_vm_init(vm);
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return (spl_val_t)(uintptr_t)vm;
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}
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/* vm_drop — destroy a sub-VM and its loaded program */
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static spl_val_t vm_drop(int nargs, spl_val_t *args) {
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CHECK_NARGS("vm_drop", 1);
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spl_vm_t *vm = (spl_vm_t *)(uintptr_t)args[0];
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if (!vm)
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return 0;
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if (vm->prog) {
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spl_prog_drop(vm->prog);
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free(vm->prog);
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vm->prog = NULL;
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}
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spl_vm_drop(vm);
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free(vm);
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return 0;
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}
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/* vm_load — load a .sir file, register syscalls, return spl_prog_t* */
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static spl_val_t vm_load(int nargs, spl_val_t *args) {
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CHECK_NARGS("vm_load", 2);
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spl_vm_t *vm = (spl_vm_t *)(uintptr_t)args[0];
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const char *path = (const char *)(uintptr_t)args[1];
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if (!vm || !path)
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return -1;
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spl_prog_t *prog = (spl_prog_t *)malloc(sizeof(spl_prog_t));
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if (!prog)
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return -1;
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if (spl_prog_load_from_file(path, prog) != 0) {
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free(prog);
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return -1;
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}
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spl_syscall_register(prog);
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if (spl_vm_load_prog(vm, prog) != 0) {
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spl_prog_drop(prog);
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free(prog);
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return -1;
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}
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return (spl_val_t)(uintptr_t)prog;
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}
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/* vm_push — push a value onto the sub-VM's stack (for passing arguments) */
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static spl_val_t vm_push(int nargs, spl_val_t *args) {
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CHECK_NARGS("vm_push", 2);
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spl_vm_t *vm = (spl_vm_t *)(uintptr_t)args[0];
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spl_val_t val = args[1];
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if (!vm)
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return -1;
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if (vm->sp >= vm->config.max_stack_depth) {
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fprintf(stderr, "vm_push: stack overflow\n");
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return -1;
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}
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vm->stacks.data[vm->sp++] = val;
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return 0;
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}
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/* vm_call — call a function by name with pre-pushed arguments
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*
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* Args (3): vm, function_name, nargs
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* The arguments should already be on the sub-VM's stack via vm_push.
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*
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* Mirrors the CALL instruction's frame setup:
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* - Pushes a sentinel frame (saved_ip=-1) if cp==0 so RET halts properly
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* - Pushes the actual call frame
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* - Sets fp = sp - nargs (so arg0 = data[fp], arg1 = data[fp+1], ...)
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* - Sets ip to the function address
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*/
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static spl_val_t vm_call(int nargs, spl_val_t *args) {
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CHECK_NARGS("vm_call", 3);
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spl_vm_t *vm = (spl_vm_t *)(uintptr_t)args[0];
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const char *name = (const char *)(uintptr_t)args[1];
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spl_val_t call_nargs = args[2];
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if (!vm || !name)
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return -1;
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spl_func_t *func = spl_prog_get_func(vm->prog, name);
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if (!func) {
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fprintf(stderr, "vm_call: function '%s' not found\n", name);
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return -1;
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}
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if (vm->cp >= vm->config.max_call_depth - 1) {
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fprintf(stderr, "vm_call: call stack overflow\n");
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return -1;
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}
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/* Sentinel frame so the entry function's RET halts cleanly */
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if (vm->cp == 0) {
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vm->frames.data[vm->cp].saved_fp = 0;
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vm->frames.data[vm->cp].saved_ip = (uintptr_t)-1;
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vm->frames.data[vm->cp].nargs = 0;
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vm->cp++;
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}
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/* Actual call frame (same logic as the CALL instruction) */
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vm->frames.data[vm->cp].saved_fp = vm->fp;
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vm->frames.data[vm->cp].saved_ip = vm->ip;
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vm->frames.data[vm->cp].nargs = call_nargs;
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vm->cp++;
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vm->fp = vm->sp - call_nargs;
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vm->ip = (uintptr_t)func->address;
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return 0;
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}
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/* vm_run — run a sub-VM to completion, returns exit_code */
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SYSCALL_1(vm_run, spl_vm_t *, spl_vm_run_until(a1, 0))
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/* =================================================================
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* Registration
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*
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* Called after loading a .sir file. Matches native declarations in
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* prog->natives against known syscall names and hooks up impl_fn.
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* ================================================================= */
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void spl_syscall_register(spl_prog_t *prog) {
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static spl_native_t table[] = {
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/* OS operations */
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{"os_exit", 0, os_exit},
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{"os_putchar", 0, os_putchar},
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{"os_getchar", 0, os_getchar},
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{"os_putint", 0, os_putint},
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{"os_putstr", 0, os_putstr},
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{"os_fopen", 0, os_fopen},
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{"os_fclose", 0, os_fclose},
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{"os_fread", 0, os_fread},
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{"os_fwrite", 0, os_fwrite},
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{"os_fsize", 0, os_fsize},
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{"os_read_file", 0, os_read_file},
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{"os_alloc", 0, os_alloc},
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{"os_free", 0, os_free},
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{"os_realloc", 0, os_realloc},
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{"os_strlen", 0, os_strlen},
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{"os_strcmp", 0, os_strcmp},
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{"os_memcpy", 0, os_memcpy},
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/* VM operations (comptime) */
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{"vm_new", 0, vm_new},
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{"vm_drop", 0, vm_drop},
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{"vm_load", 0, vm_load},
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{"vm_push", 0, vm_push},
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{"vm_call", 0, vm_call},
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{"vm_run", 0, vm_run},
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};
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int n = (int)(sizeof(table) / sizeof(table[0]));
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if (!prog)
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return;
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vec_for(prog->natives, i) {
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spl_native_t *nat = &vec_at(prog->natives, i);
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if (!nat->name || nat->impl_fn)
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continue;
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for (int j = 0; j < n; j++) {
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if (strcmp(nat->name, table[j].name) == 0) {
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nat->impl_fn = table[j].impl_fn;
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break;
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}
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}
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}
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}
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