forked from OSchip/llvm-project
68 lines
1.8 KiB
ArmAsm
68 lines
1.8 KiB
ArmAsm
// This file is dual licensed under the MIT and the University of Illinois Open
|
|
// Source Licenses. See LICENSE.TXT for details.
|
|
|
|
#include "../assembly.h"
|
|
|
|
// di_int __ashrdi3(di_int input, int count);
|
|
|
|
#ifdef __i386__
|
|
#ifdef __SSE2__
|
|
|
|
.text
|
|
.align 4
|
|
DEFINE_COMPILERRT_FUNCTION(__ashrdi3)
|
|
movd 12(%esp), %xmm2 // Load count
|
|
movl 8(%esp), %eax
|
|
#ifndef TRUST_CALLERS_USE_64_BIT_STORES
|
|
movd 4(%esp), %xmm0
|
|
movd 8(%esp), %xmm1
|
|
punpckldq %xmm1, %xmm0 // Load input
|
|
#else
|
|
movq 4(%esp), %xmm0 // Load input
|
|
#endif
|
|
|
|
psrlq %xmm2, %xmm0 // unsigned shift input by count
|
|
|
|
testl %eax, %eax // check the sign-bit of the input
|
|
jns 1f // early out for positive inputs
|
|
|
|
// If the input is negative, we need to construct the shifted sign bit
|
|
// to or into the result, as xmm does not have a signed right shift.
|
|
pcmpeqb %xmm1, %xmm1 // -1ULL
|
|
psrlq $58, %xmm1 // 0x3f
|
|
pandn %xmm1, %xmm2 // 63 - count
|
|
pcmpeqb %xmm1, %xmm1 // -1ULL
|
|
psubq %xmm1, %xmm2 // 64 - count
|
|
psllq %xmm2, %xmm1 // -1 << (64 - count) = leading sign bits
|
|
por %xmm1, %xmm0
|
|
|
|
// Move the result back to the general purpose registers and return
|
|
1: movd %xmm0, %eax
|
|
psrlq $32, %xmm0
|
|
movd %xmm0, %edx
|
|
ret
|
|
|
|
#else // Use GPRs instead of SSE2 instructions, if they aren't available.
|
|
|
|
.text
|
|
.align 4
|
|
DEFINE_COMPILERRT_FUNCTION(__ashrdi3)
|
|
movl 12(%esp), %ecx // Load count
|
|
movl 8(%esp), %edx // Load high
|
|
movl 4(%esp), %eax // Load low
|
|
|
|
testl $0x20, %ecx // If count >= 32
|
|
jnz 1f // goto 1
|
|
|
|
shrdl %cl, %edx, %eax // right shift low by count
|
|
sarl %cl, %edx // right shift high by count
|
|
ret
|
|
|
|
1: movl %edx, %eax // Move high to low
|
|
sarl $31, %edx // clear high
|
|
sarl %cl, %eax // shift low by count - 32
|
|
ret
|
|
|
|
#endif // __SSE2__
|
|
#endif // __i386__
|