os_kernel_lab/related_info/lab5/lab5-spoc-discuss/user/libs/syscall.c

#include <defs.h>
#include <unistd.h>
#include <stdarg.h>
#include <syscall.h>

#define MAX_ARGS            5

static inline int
syscall(int num, ...) {
    va_list ap;
    va_start(ap, num);
    uint32_t a[MAX_ARGS];
    int i, ret;
    for (i = 0; i < MAX_ARGS; i ++) {
        a[i] = va_arg(ap, uint32_t);
    }
    va_end(ap);

    asm volatile (
        "int %1;"
        : "=a" (ret)
        : "i" (T_SYSCALL),
          "a" (num),
          "d" (a[0]),
          "c" (a[1]),
          "b" (a[2]),
          "D" (a[3]),
          "S" (a[4])
        : "cc", "memory");
    return ret;
}

int
sys_exit(int error_code) {
    return syscall(SYS_exit, error_code);
}

int
sys_fork(void) {
    return syscall(SYS_fork);
}

int
sys_wait(int pid, int *store) {
    return syscall(SYS_wait, pid, store);
}

int
sys_yield(void) {
    return syscall(SYS_yield);
}

int
sys_kill(int pid) {
    return syscall(SYS_kill, pid);
}

int
sys_getpid(void) {
    return syscall(SYS_getpid);
}

int
sys_putc(int c) {
    return syscall(SYS_putc, c);
}

int
sys_pgdir(void) {
    return syscall(SYS_pgdir);
}