ashrdi3.S revision 1.1.1.2.4.2
1 // This file is dual licensed under the MIT and the University of Illinois Open 2 // Source Licenses. See LICENSE.TXT for details. 3 4 #include "../assembly.h" 5 6 // di_int __ashrdi3(di_int input, int count); 7 8 #ifdef __i386__ 9 #ifdef __SSE2__ 10 11 .text 12 .align 4 13 DEFINE_COMPILERRT_FUNCTION(__ashrdi3) 14 movd 12(%esp), %xmm2 // Load count 15 movl 8(%esp), %eax 16 #ifndef TRUST_CALLERS_USE_64_BIT_STORES 17 movd 4(%esp), %xmm0 18 movd 8(%esp), %xmm1 19 punpckldq %xmm1, %xmm0 // Load input 20 #else 21 movq 4(%esp), %xmm0 // Load input 22 #endif 23 24 psrlq %xmm2, %xmm0 // unsigned shift input by count 25 26 testl %eax, %eax // check the sign-bit of the input 27 jns 1f // early out for positive inputs 28 29 // If the input is negative, we need to construct the shifted sign bit 30 // to or into the result, as xmm does not have a signed right shift. 31 pcmpeqb %xmm1, %xmm1 // -1ULL 32 psrlq $58, %xmm1 // 0x3f 33 pandn %xmm1, %xmm2 // 63 - count 34 pcmpeqb %xmm1, %xmm1 // -1ULL 35 psubq %xmm1, %xmm2 // 64 - count 36 psllq %xmm2, %xmm1 // -1 << (64 - count) = leading sign bits 37 por %xmm1, %xmm0 38 39 // Move the result back to the general purpose registers and return 40 1: movd %xmm0, %eax 41 psrlq $32, %xmm0 42 movd %xmm0, %edx 43 ret 44 END_COMPILERRT_FUNCTION(__ashrdi3) 45 46 #else // Use GPRs instead of SSE2 instructions, if they aren't available. 47 48 .text 49 .align 4 50 DEFINE_COMPILERRT_FUNCTION(__ashrdi3) 51 movl 12(%esp), %ecx // Load count 52 movl 8(%esp), %edx // Load high 53 movl 4(%esp), %eax // Load low 54 55 testl $0x20, %ecx // If count >= 32 56 jnz 1f // goto 1 57 58 shrdl %cl, %edx, %eax // right shift low by count 59 sarl %cl, %edx // right shift high by count 60 ret 61 62 1: movl %edx, %eax // Move high to low 63 sarl $31, %edx // clear high 64 sarl %cl, %eax // shift low by count - 32 65 ret 66 END_COMPILERRT_FUNCTION(__ashrdi3) 67 68 #endif // __SSE2__ 69 #endif // __i386__ 70
Indexes created Thu Oct 02 14:10:14 GMT 2025