cosmopolitan/libc/sysv/macros.internal.h
Justine Tunney ae0ee59614
Get aarch64 hello world working
$ m=aarch64-tiny
    $ make -j8 m=$m o/$m/tool/hello/hello.com o/third_party/qemu/qemu-aarch64
    $ o/third_party/qemu/qemu-aarch64 o/$m/tool/hello/hello.com
    hello world
    $ ls -hal o/$m/tool/hello/hello.com
    -rwxr-xr-x 1 jart jart 4.0K May  9 05:04 o/aarch64-tiny/tool/hello/hello.com
2023-05-10 04:20:47 -07:00

48 lines
1.2 KiB
C

#ifndef COSMOPOLITAN_LIBC_SYSV_MACROS_H_
#define COSMOPOLITAN_LIBC_SYSV_MACROS_H_
#include "libc/macros.internal.h"
#ifdef __ASSEMBLER__
/* clang-format off */
/**
* @fileoverview System Five jump slot generator.
*
* We need to pass a magic number to the SYSCALL instruction in %rax.
* That's only possible to do in C using asm() macro wrappers, like in
* Chromium's "System Call Support" library. This technique is simpler
* to implement, gains us object-level ABI compatibility, hookability,
* and the ability to support significantly more functions, without the
* risk of slowing down builds too much with complicated headers.
*/
.macro .scall name:req amd:req arm:req kw1 kw2
.section .text.syscall,"ax",@progbits
#ifdef __x86_64__
.ifnb \kw2
.align 16
\name: movabs $\amd,%rax
jmp *__systemfive(%rip)
.else
\name: push %rbp
mov %rsp,%rbp
movabs $\amd,%rax
.hookable
call *__systemfive(%rip)
pop %rbp
ret
.endif
#elif defined(__aarch64__)
\name: mov x8,#\arm
svc #0
b _sysret
.hidden _sysret
#else
#error "architecture unsupported"
#endif
.endfn \name,\kw1,\kw2
.previous
.endm
/* clang-format on */
#endif /* __ASSEMBLER__ */
#endif /* COSMOPOLITAN_LIBC_SYSV_MACROS_H_ */