minix/lib/libc/arch/i386/int64/sub64.S
Lorenzo Cavallaro a16308efdb cdecl calling convention expects the callee to pop the hidden pointer on
struct return. For example, GCC and LLVM comply with this (tested on IA32).

ACK doesn't seem to follow this convention and expects the caller to clean up
the stack. Compiling hand-written ACK-compliant assembly code (returning a 
struct) with GCC or LLVM used to break things (4-bytes misaligned stack).

The patch fixes this problem.
2010-03-24 17:25:17 +00:00

20 lines
425 B
ArmAsm

/* sub64() - 64 bit subtraction Author: Kees J. Bot */
/* 7 Dec 1995 */
#include <minix/compiler.h>
.text
.globl _sub64
_sub64:
/* u64_t sub64(u64_t i, u64_t j); */
movl 4(%esp), %eax
movl 8(%esp), %edx
subl 16(%esp), %edx
movl %edx, (%eax)
movl 12(%esp), %edx
sbbl 20(%esp), %edx
movl %edx, 4(%eax)
ret BYTES_TO_POP_ON_STRUCT_RETURN
/* */
/* $PchId: sub64.ack.s,v 1.2 1996/04/11 18:59:57 philip Exp $ */