diff options
Diffstat (limited to 'scripts/romload/syscalls.c')
-rw-r--r-- | scripts/romload/syscalls.c | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/scripts/romload/syscalls.c b/scripts/romload/syscalls.c new file mode 100644 index 0000000..8ea84ca --- /dev/null +++ b/scripts/romload/syscalls.c @@ -0,0 +1,95 @@ +// An extremely minimalist syscalls.c for newlib +// Based on riscv newlib libgloss/riscv/sys_*.c +// Written by Clifford Wolf. + +#include <sys/stat.h> +#include <unistd.h> +#include <errno.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 ("ebreak"); + __builtin_unreachable(); +} + |