picorv32/dhrystone/syscalls.c

71 lines
2.1 KiB
C

// An extremely minimalist syscalls.c for newlib
// Based on riscv newlib libgloss/riscv/sys_*.c
// Written by Clifford Wolf.
#include <errno.h>
#include <sys/stat.h>
#include <unistd.h>
#define UNIMPL_FUNC(_f) ".globl " #_f "\n.type " #_f ", @function\n" #_f ":\n"
asm(".text\n"
".align 2\n" UNIMPL_FUNC(_open) UNIMPL_FUNC(_openat) UNIMPL_FUNC(_lseek)
UNIMPL_FUNC(_stat) UNIMPL_FUNC(_lstat) UNIMPL_FUNC(_fstatat)
UNIMPL_FUNC(_isatty) UNIMPL_FUNC(_access) UNIMPL_FUNC(_faccessat)
UNIMPL_FUNC(_link) UNIMPL_FUNC(_unlink) UNIMPL_FUNC(_execve)
UNIMPL_FUNC(_getpid) UNIMPL_FUNC(_fork) UNIMPL_FUNC(_kill)
UNIMPL_FUNC(_wait) UNIMPL_FUNC(_times) UNIMPL_FUNC(
_gettimeofday) UNIMPL_FUNC(_ftime)
UNIMPL_FUNC(_utime) UNIMPL_FUNC(_chown)
UNIMPL_FUNC(_chmod) UNIMPL_FUNC(_chdir)
UNIMPL_FUNC(_getcwd) UNIMPL_FUNC(
_sysconf) "j unimplemented_syscall\n");
void unimplemented_syscall() {
const char *p = "Unimplemented system call called!\n";
while (*p) *(volatile int *)0x10000000 = *(p++);
asm volatile("ebreak");
__builtin_unreachable();
}
ssize_t _read(int file, void *ptr, size_t len) {
// always EOF
return 0;
}
ssize_t _write(int file, const void *ptr, size_t len) {
const void *eptr = ptr + len;
while (ptr != eptr) *(volatile int *)0x10000000 = *(char *)(ptr++);
return len;
}
int _close(int file) {
// close is called before _exit()
return 0;
}
int _fstat(int file, struct stat *st) {
// fstat is called during libc startup
errno = ENOENT;
return -1;
}
void *_sbrk(ptrdiff_t incr) {
extern unsigned char _end[]; // Defined by linker
static unsigned long heap_end;
if (heap_end == 0) heap_end = (long)_end;
heap_end += incr;
return (void *)(heap_end - incr);
}
void _exit(int exit_status) {
asm volatile("li a0, 0x20000000");
asm volatile("li a1, 123456789");
asm volatile("sw a1,0(a0)");
asm volatile("ebreak");
__builtin_unreachable();
}