// Copyright 2009 The Go Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. // System calls and other sys.stuff for 386, Darwin // System calls are implemented in libSystem, this file contains // trampolines that convert from Go to C calling convention. #include "go_asm.h" #include "go_tls.h" #include "textflag.h" // Exit the entire program (like C exit) TEXT runtime·exit_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $8, SP // allocate space for callee args (must be 8 mod 16) MOVL 16(SP), CX // arg ptr MOVL 0(CX), AX // arg 1 exit status MOVL AX, 0(SP) CALL libc_exit(SB) MOVL $0xf1, 0xf1 // crash MOVL BP, SP POPL BP RET TEXT runtime·open_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $24, SP MOVL 32(SP), CX MOVL 0(CX), AX // arg 1 name MOVL AX, 0(SP) MOVL 4(CX), AX // arg 2 mode MOVL AX, 4(SP) MOVL 8(CX), AX // arg 3 perm MOVL AX, 8(SP) CALL libc_open(SB) MOVL BP, SP POPL BP RET TEXT runtime·close_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $8, SP MOVL 16(SP), CX MOVL 0(CX), AX // arg 1 fd MOVL AX, 0(SP) CALL libc_close(SB) MOVL BP, SP POPL BP RET TEXT runtime·read_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $24, SP MOVL 32(SP), CX MOVL 0(CX), AX // arg 1 fd MOVL AX, 0(SP) MOVL 4(CX), AX // arg 2 buf MOVL AX, 4(SP) MOVL 8(CX), AX // arg 3 count MOVL AX, 8(SP) CALL libc_read(SB) MOVL BP, SP POPL BP RET TEXT runtime·write_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $24, SP MOVL 32(SP), CX MOVL 0(CX), AX // arg 1 fd MOVL AX, 0(SP) MOVL 4(CX), AX // arg 2 buf MOVL AX, 4(SP) MOVL 8(CX), AX // arg 3 count MOVL AX, 8(SP) CALL libc_write(SB) MOVL BP, SP POPL BP RET TEXT runtime·mmap_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $24, SP MOVL 32(SP), CX MOVL 0(CX), AX // arg 1 addr MOVL AX, 0(SP) MOVL 4(CX), AX // arg 2 len MOVL AX, 4(SP) MOVL 8(CX), AX // arg 3 prot MOVL AX, 8(SP) MOVL 12(CX), AX // arg 4 flags MOVL AX, 12(SP) MOVL 16(CX), AX // arg 5 fid MOVL AX, 16(SP) MOVL 20(CX), AX // arg 6 offset MOVL AX, 20(SP) CALL libc_mmap(SB) XORL DX, DX CMPL AX, $-1 JNE ok CALL libc_error(SB) MOVL (AX), DX // errno XORL AX, AX ok: MOVL 32(SP), CX MOVL AX, 24(CX) // result pointer MOVL DX, 28(CX) // errno MOVL BP, SP POPL BP RET TEXT runtime·madvise_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $24, SP MOVL 32(SP), CX MOVL 0(CX), AX // arg 1 addr MOVL AX, 0(SP) MOVL 4(CX), AX // arg 2 len MOVL AX, 4(SP) MOVL 8(CX), AX // arg 3 advice MOVL AX, 8(SP) CALL libc_madvise(SB) // ignore failure - maybe pages are locked MOVL BP, SP POPL BP RET TEXT runtime·munmap_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $8, SP MOVL 16(SP), CX MOVL 0(CX), AX // arg 1 addr MOVL AX, 0(SP) MOVL 4(CX), AX // arg 2 len MOVL AX, 4(SP) CALL libc_munmap(SB) TESTL AX, AX JEQ 2(PC) MOVL $0xf1, 0xf1 // crash MOVL BP, SP POPL BP RET TEXT runtime·setitimer_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $24, SP MOVL 32(SP), CX MOVL 0(CX), AX // arg 1 mode MOVL AX, 0(SP) MOVL 4(CX), AX // arg 2 new MOVL AX, 4(SP) MOVL 8(CX), AX // arg 3 old MOVL AX, 8(SP) CALL libc_setitimer(SB) MOVL BP, SP POPL BP RET TEXT runtime·walltime_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $8, SP MOVL 16(SP), AX MOVL AX, 0(SP) // *timeval MOVL $0, 4(SP) // no timezone needed CALL libc_gettimeofday(SB) MOVL BP, SP POPL BP RET GLOBL timebase<>(SB),NOPTR,$(machTimebaseInfo__size) TEXT runtime·nanotime_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $8+(machTimebaseInfo__size+15)/16*16, SP CALL libc_mach_absolute_time(SB) MOVL 16+(machTimebaseInfo__size+15)/16*16(SP), CX MOVL AX, 0(CX) MOVL DX, 4(CX) MOVL timebase<>+machTimebaseInfo_denom(SB), DI // atomic read MOVL timebase<>+machTimebaseInfo_numer(SB), SI TESTL DI, DI JNE initialized LEAL 4(SP), AX MOVL AX, 0(SP) CALL libc_mach_timebase_info(SB) MOVL 4+machTimebaseInfo_numer(SP), SI MOVL 4+machTimebaseInfo_denom(SP), DI MOVL SI, timebase<>+machTimebaseInfo_numer(SB) MOVL DI, AX XCHGL AX, timebase<>+machTimebaseInfo_denom(SB) // atomic write MOVL 16+(machTimebaseInfo__size+15)/16*16(SP), CX initialized: MOVL SI, 8(CX) MOVL DI, 12(CX) MOVL BP, SP POPL BP RET TEXT runtime·sigaction_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $24, SP MOVL 32(SP), CX MOVL 0(CX), AX // arg 1 sig MOVL AX, 0(SP) MOVL 4(CX), AX // arg 2 new MOVL AX, 4(SP) MOVL 8(CX), AX // arg 3 old MOVL AX, 8(SP) CALL libc_sigaction(SB) TESTL AX, AX JEQ 2(PC) MOVL $0xf1, 0xf1 // crash MOVL BP, SP POPL BP RET TEXT runtime·sigprocmask_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $24, SP MOVL 32(SP), CX MOVL 0(CX), AX // arg 1 how MOVL AX, 0(SP) MOVL 4(CX), AX // arg 2 new MOVL AX, 4(SP) MOVL 8(CX), AX // arg 3 old MOVL AX, 8(SP) CALL libc_pthread_sigmask(SB) TESTL AX, AX JEQ 2(PC) MOVL $0xf1, 0xf1 // crash MOVL BP, SP POPL BP RET TEXT runtime·sigaltstack_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $8, SP MOVL 16(SP), CX MOVL 0(CX), AX // arg 1 new MOVL AX, 0(SP) MOVL 4(CX), AX // arg 2 old MOVL AX, 4(SP) CALL libc_sigaltstack(SB) TESTL AX, AX JEQ 2(PC) MOVL $0xf1, 0xf1 // crash MOVL BP, SP POPL BP RET TEXT runtime·raiseproc_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $8, SP CALL libc_getpid(SB) MOVL AX, 0(SP) // arg 1 pid MOVL 16(SP), CX MOVL 0(CX), AX MOVL AX, 4(SP) // arg 2 signal CALL libc_kill(SB) MOVL BP, SP POPL BP RET TEXT runtime·sigfwd(SB),NOSPLIT,$0-16 MOVL fn+0(FP), AX MOVL sig+4(FP), BX MOVL info+8(FP), CX MOVL ctx+12(FP), DX MOVL SP, SI SUBL $32, SP ANDL $~15, SP // align stack: handler might be a C function MOVL BX, 0(SP) MOVL CX, 4(SP) MOVL DX, 8(SP) MOVL SI, 12(SP) // save SI: handler might be a Go function CALL AX MOVL 12(SP), AX MOVL AX, SP RET // Sigtramp's job is to call the actual signal handler. // It is called with the C calling convention, and calls out // to sigtrampgo with the Go calling convention. TEXT runtime·sigtramp(SB),NOSPLIT,$0 SUBL $28, SP // Save callee-save registers. MOVL BP, 12(SP) MOVL BX, 16(SP) MOVL SI, 20(SP) MOVL DI, 24(SP) MOVL 32(SP), AX MOVL AX, 0(SP) // arg 1 signal number MOVL 36(SP), AX MOVL AX, 4(SP) // arg 2 siginfo MOVL 40(SP), AX MOVL AX, 8(SP) // arg 3 ctxt CALL runtime·sigtrampgo(SB) // Restore callee-save registers. MOVL 12(SP), BP MOVL 16(SP), BX MOVL 20(SP), SI MOVL 24(SP), DI ADDL $28, SP RET TEXT runtime·cgoSigtramp(SB),NOSPLIT,$0 JMP runtime·sigtramp(SB) TEXT runtime·usleep_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $8, SP MOVL 16(SP), CX MOVL 0(CX), AX // arg 1 usec MOVL AX, 0(SP) CALL libc_usleep(SB) MOVL BP, SP POPL BP RET // func setldt(entry int, address int, limit int) TEXT runtime·setldt(SB),NOSPLIT,$32 // Nothing to do on Darwin, pthread already set thread-local storage up. RET TEXT runtime·sysctl_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $24, SP MOVL 32(SP), CX MOVL 0(CX), AX // arg 1 mib MOVL AX, 0(SP) MOVL 4(CX), AX // arg 2 miblen MOVL AX, 4(SP) MOVL 8(CX), AX // arg 3 out MOVL AX, 8(SP) MOVL 12(CX), AX // arg 4 size MOVL AX, 12(SP) MOVL 16(CX), AX // arg 5 dst MOVL AX, 16(SP) MOVL 20(CX), AX // arg 6 ndst MOVL AX, 20(SP) CALL libc_sysctl(SB) MOVL BP, SP POPL BP RET TEXT runtime·kqueue_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $8, SP CALL libc_kqueue(SB) MOVL BP, SP POPL BP RET TEXT runtime·kevent_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $24, SP MOVL 32(SP), CX MOVL 0(CX), AX // arg 1 kq MOVL AX, 0(SP) MOVL 4(CX), AX // arg 2 ch MOVL AX, 4(SP) MOVL 8(CX), AX // arg 3 nch MOVL AX, 8(SP) MOVL 12(CX), AX // arg 4 ev MOVL AX, 12(SP) MOVL 16(CX), AX // arg 5 nev MOVL AX, 16(SP) MOVL 20(CX), AX // arg 6 ts MOVL AX, 20(SP) CALL libc_kevent(SB) CMPL AX, $-1 JNE ok CALL libc_error(SB) MOVL (AX), AX // errno NEGL AX // caller wants it as a negative error code ok: MOVL BP, SP POPL BP RET TEXT runtime·fcntl_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $24, SP MOVL 32(SP), CX MOVL 0(CX), AX // arg 1 fd MOVL AX, 0(SP) MOVL 4(CX), AX // arg 2 cmd MOVL AX, 4(SP) MOVL 8(CX), AX // arg 3 arg MOVL AX, 8(SP) CALL libc_fcntl(SB) MOVL BP, SP POPL BP RET // mstart_stub is the first function executed on a new thread started by pthread_create. // It just does some low-level setup and then calls mstart. // Note: called with the C calling convention. TEXT runtime·mstart_stub(SB),NOSPLIT,$0 // The value at SP+4 points to the m. // We are already on m's g0 stack. // Save callee-save registers. SUBL $16, SP MOVL BP, 0(SP) MOVL BX, 4(SP) MOVL SI, 8(SP) MOVL DI, 12(SP) MOVL SP, AX // hide argument read from vet (vet thinks this function is using the Go calling convention) MOVL 20(AX), DI // m MOVL m_g0(DI), DX // g // Initialize TLS entry. // See cmd/link/internal/ld/sym.go:computeTLSOffset. MOVL DX, 0x18(GS) // Someday the convention will be D is always cleared. CLD CALL runtime·mstart(SB) // Restore callee-save registers. MOVL 0(SP), BP MOVL 4(SP), BX MOVL 8(SP), SI MOVL 12(SP), DI // Go is all done with this OS thread. // Tell pthread everything is ok (we never join with this thread, so // the value here doesn't really matter). XORL AX, AX ADDL $16, SP RET TEXT runtime·pthread_attr_init_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $8, SP MOVL 16(SP), CX MOVL 0(CX), AX // arg 1 attr MOVL AX, 0(SP) CALL libc_pthread_attr_init(SB) MOVL BP, SP POPL BP RET TEXT runtime·pthread_attr_setstacksize_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $8, SP MOVL 16(SP), CX MOVL 0(CX), AX // arg 1 attr MOVL AX, 0(SP) MOVL 4(CX), AX // arg 2 size MOVL AX, 4(SP) CALL libc_pthread_attr_setstacksize(SB) MOVL BP, SP POPL BP RET TEXT runtime·pthread_attr_setdetachstate_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $8, SP MOVL 16(SP), CX MOVL 0(CX), AX // arg 1 attr MOVL AX, 0(SP) MOVL 4(CX), AX // arg 2 state MOVL AX, 4(SP) CALL libc_pthread_attr_setdetachstate(SB) MOVL BP, SP POPL BP RET TEXT runtime·pthread_create_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $24, SP MOVL 32(SP), CX LEAL 16(SP), AX // arg "0" &threadid (which we throw away) MOVL AX, 0(SP) MOVL 0(CX), AX // arg 1 attr MOVL AX, 4(SP) MOVL 4(CX), AX // arg 2 start MOVL AX, 8(SP) MOVL 8(CX), AX // arg 3 arg MOVL AX, 12(SP) CALL libc_pthread_create(SB) MOVL BP, SP POPL BP RET TEXT runtime·raise_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $8, SP MOVL 16(SP), CX MOVL 0(CX), AX // arg 1 sig MOVL AX, 0(SP) CALL libc_raise(SB) MOVL BP, SP POPL BP RET TEXT runtime·pthread_mutex_init_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $8, SP MOVL 16(SP), CX MOVL 0(CX), AX // arg 1 mutex MOVL AX, 0(SP) MOVL 4(CX), AX // arg 2 attr MOVL AX, 4(SP) CALL libc_pthread_mutex_init(SB) MOVL BP, SP POPL BP RET TEXT runtime·pthread_mutex_lock_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $8, SP MOVL 16(SP), CX MOVL 0(CX), AX // arg 1 mutex MOVL AX, 0(SP) CALL libc_pthread_mutex_lock(SB) MOVL BP, SP POPL BP RET TEXT runtime·pthread_mutex_unlock_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $8, SP MOVL 16(SP), CX MOVL 0(CX), AX // arg 1 mutex MOVL AX, 0(SP) CALL libc_pthread_mutex_unlock(SB) MOVL BP, SP POPL BP RET TEXT runtime·pthread_cond_init_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $8, SP MOVL 16(SP), CX MOVL 0(CX), AX // arg 1 cond MOVL AX, 0(SP) MOVL 4(CX), AX // arg 2 attr MOVL AX, 4(SP) CALL libc_pthread_cond_init(SB) MOVL BP, SP POPL BP RET TEXT runtime·pthread_cond_wait_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $8, SP MOVL 16(SP), CX MOVL 0(CX), AX // arg 1 cond MOVL AX, 0(SP) MOVL 4(CX), AX // arg 2 mutex MOVL AX, 4(SP) CALL libc_pthread_cond_wait(SB) MOVL BP, SP POPL BP RET TEXT runtime·pthread_cond_timedwait_relative_np_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $24, SP MOVL 32(SP), CX MOVL 0(CX), AX // arg 1 cond MOVL AX, 0(SP) MOVL 4(CX), AX // arg 2 mutex MOVL AX, 4(SP) MOVL 8(CX), AX // arg 3 timeout MOVL AX, 8(SP) CALL libc_pthread_cond_timedwait_relative_np(SB) MOVL BP, SP POPL BP RET TEXT runtime·pthread_cond_signal_trampoline(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $8, SP MOVL 16(SP), CX MOVL 0(CX), AX // arg 1 cond MOVL AX, 0(SP) CALL libc_pthread_cond_signal(SB) MOVL BP, SP POPL BP RET // syscall calls a function in libc on behalf of the syscall package. // syscall takes a pointer to a struct like: // struct { // fn uintptr // a1 uintptr // a2 uintptr // a3 uintptr // r1 uintptr // r2 uintptr // err uintptr // } // syscall must be called on the g0 stack with the // C calling convention (use libcCall). TEXT runtime·syscall(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $24, SP MOVL 32(SP), CX MOVL (0*4)(CX), AX // fn MOVL (1*4)(CX), DX // a1 MOVL DX, 0(SP) MOVL (2*4)(CX), DX // a2 MOVL DX, 4(SP) MOVL (3*4)(CX), DX // a3 MOVL DX, 8(SP) CALL AX MOVL 32(SP), CX MOVL AX, (4*4)(CX) // r1 MOVL DX, (5*4)(CX) // r2 // Standard libc functions return -1 on error // and set errno. CMPL AX, $-1 JNE ok // Get error code from libc. CALL libc_error(SB) MOVL (AX), AX MOVL 32(SP), CX MOVL AX, (6*4)(CX) // err ok: XORL AX, AX // no error (it's ignored anyway) MOVL BP, SP POPL BP RET // Not used on 386. TEXT runtime·syscallPtr(SB),NOSPLIT,$0 MOVL $0xf1, 0xf1 // crash RET // syscall6 calls a function in libc on behalf of the syscall package. // syscall6 takes a pointer to a struct like: // struct { // fn uintptr // a1 uintptr // a2 uintptr // a3 uintptr // a4 uintptr // a5 uintptr // a6 uintptr // r1 uintptr // r2 uintptr // err uintptr // } // syscall6 must be called on the g0 stack with the // C calling convention (use libcCall). TEXT runtime·syscall6(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $24, SP MOVL 32(SP), CX MOVL (0*4)(CX), AX // fn MOVL (1*4)(CX), DX // a1 MOVL DX, 0(SP) MOVL (2*4)(CX), DX // a2 MOVL DX, 4(SP) MOVL (3*4)(CX), DX // a3 MOVL DX, 8(SP) MOVL (4*4)(CX), DX // a4 MOVL DX, 12(SP) MOVL (5*4)(CX), DX // a5 MOVL DX, 16(SP) MOVL (6*4)(CX), DX // a6 MOVL DX, 20(SP) CALL AX MOVL 32(SP), CX MOVL AX, (7*4)(CX) // r1 MOVL DX, (8*4)(CX) // r2 // Standard libc functions return -1 on error // and set errno. CMPL AX, $-1 JNE ok // Get error code from libc. CALL libc_error(SB) MOVL (AX), AX MOVL 32(SP), CX MOVL AX, (9*4)(CX) // err ok: XORL AX, AX // no error (it's ignored anyway) MOVL BP, SP POPL BP RET // syscall6X calls a function in libc on behalf of the syscall package. // syscall6X takes a pointer to a struct like: // struct { // fn uintptr // a1 uintptr // a2 uintptr // a3 uintptr // a4 uintptr // a5 uintptr // a6 uintptr // r1 uintptr // r2 uintptr // err uintptr // } // syscall6X must be called on the g0 stack with the // C calling convention (use libcCall). TEXT runtime·syscall6X(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $24, SP MOVL 32(SP), CX MOVL (0*4)(CX), AX // fn MOVL (1*4)(CX), DX // a1 MOVL DX, 0(SP) MOVL (2*4)(CX), DX // a2 MOVL DX, 4(SP) MOVL (3*4)(CX), DX // a3 MOVL DX, 8(SP) MOVL (4*4)(CX), DX // a4 MOVL DX, 12(SP) MOVL (5*4)(CX), DX // a5 MOVL DX, 16(SP) MOVL (6*4)(CX), DX // a6 MOVL DX, 20(SP) CALL AX MOVL 32(SP), CX MOVL AX, (7*4)(CX) // r1 MOVL DX, (8*4)(CX) // r2 // Standard libc functions return -1 on error // and set errno. CMPL AX, $-1 JNE ok CMPL DX, $-1 JNE ok // Get error code from libc. CALL libc_error(SB) MOVL (AX), AX MOVL 32(SP), CX MOVL AX, (9*4)(CX) // err ok: XORL AX, AX // no error (it's ignored anyway) MOVL BP, SP POPL BP RET // syscall9 calls a function in libc on behalf of the syscall package. // syscall9 takes a pointer to a struct like: // struct { // fn uintptr // a1 uintptr // a2 uintptr // a3 uintptr // a4 uintptr // a5 uintptr // a6 uintptr // a7 uintptr // a8 uintptr // a9 uintptr // r1 uintptr // r2 uintptr // err uintptr // } // syscall9 must be called on the g0 stack with the // C calling convention (use libcCall). TEXT runtime·syscall9(SB),NOSPLIT,$0 PUSHL BP MOVL SP, BP SUBL $40, SP MOVL 48(SP), CX MOVL (0*4)(CX), AX // fn MOVL (1*4)(CX), DX // a1 MOVL DX, 0(SP) MOVL (2*4)(CX), DX // a2 MOVL DX, 4(SP) MOVL (3*4)(CX), DX // a3 MOVL DX, 8(SP) MOVL (4*4)(CX), DX // a4 MOVL DX, 12(SP) MOVL (5*4)(CX), DX // a5 MOVL DX, 16(SP) MOVL (6*4)(CX), DX // a6 MOVL DX, 20(SP) MOVL (7*4)(CX), DX // a7 MOVL DX, 24(SP) MOVL (8*4)(CX), DX // a8 MOVL DX, 28(SP) MOVL (9*4)(CX), DX // a9 MOVL DX, 32(SP) CALL AX MOVL 48(SP), CX MOVL AX, (10*4)(CX) // r1 MOVL DX, (11*4)(CX) // r2 // Standard libc functions return -1 on error // and set errno. CMPL AX, $-1 JNE ok // Get error code from libc. CALL libc_error(SB) MOVL (AX), AX MOVL 48(SP), CX MOVL AX, (12*4)(CX) // err ok: XORL AX, AX // no error (it's ignored anyway) MOVL BP, SP POPL BP RET