| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| |
| // di_int __lshrdi3(di_int input, int count); |
| |
| // This routine has some extra memory traffic, loading the 64-bit input via two |
| // 32-bit loads, then immediately storing it back to the stack via a single 64-bit |
| // store. This is to avoid a write-small, read-large stall. |
| // However, if callers of this routine can be safely assumed to store the argument |
| // via a 64-bt store, this is unnecessary memory traffic, and should be avoided. |
| // It can be turned off by defining the TRUST_CALLERS_USE_64_BIT_STORES macro. |
| |
| #ifdef __i386__ |
| #ifdef __SSE2__ |
| |
| .text |
| .align 4 |
| .globl ___lshrdi3 |
| ___lshrdi3: |
| movd 12(%esp), %xmm2 // Load count |
| #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 // shift input by count |
| 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 |
| .globl ___lshrdi3 |
| ___lshrdi3: |
| 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 2f // goto 2 |
| testl $0x1f, %ecx // If count == 0 |
| jz 1f // goto 1 |
| |
| pushl %ebx |
| movl %edx, %ebx // copy high |
| shrl %cl, %eax // right shift low by count |
| shrl %cl, %edx // right shift high by count |
| neg %cl |
| shll %cl, %ebx // left shift high by 32 - count |
| orl %ebx, %eax // or the result into the low word |
| popl %ebx |
| 1: ret |
| |
| 2: movl %edx, %eax // Move high to low |
| xorl %edx, %edx // clear high |
| shrl %cl, %eax // shift low by count - 32 |
| ret |
| |
| #endif // __SSE2__ |
| #endif // __i386__ |