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 __lshrdi3(di_int input, int count); 7 8 // This routine has some extra memory traffic, loading the 64-bit input via two 9 // 32-bit loads, then immediately storing it back to the stack via a single 64-bit 10 // store. This is to avoid a write-small, read-large stall. 11 // However, if callers of this routine can be safely assumed to store the argument 12 // via a 64-bt store, this is unnecessary memory traffic, and should be avoided. 13 // It can be turned off by defining the TRUST_CALLERS_USE_64_BIT_STORES macro. 14 15 #ifdef __i386__ 16 #ifdef __SSE2__ 17 18 .text 19 .balign 4 20 DEFINE_COMPILERRT_FUNCTION(__lshrdi3) 21 movd 12(%esp), %xmm2 // Load count 22 #ifndef TRUST_CALLERS_USE_64_BIT_STORES 23 movd 4(%esp), %xmm0 24 movd 8(%esp), %xmm1 25 punpckldq %xmm1, %xmm0 // Load input 26 #else 27 movq 4(%esp), %xmm0 // Load input 28 #endif 29 psrlq %xmm2, %xmm0 // shift input by count 30 movd %xmm0, %eax 31 psrlq $32, %xmm0 32 movd %xmm0, %edx 33 ret 34 END_COMPILERRT_FUNCTION(__lshrdi3) 35 36 #else // Use GPRs instead of SSE2 instructions, if they aren't available. 37 38 .text 39 .balign 4 40 DEFINE_COMPILERRT_FUNCTION(__lshrdi3) 41 movl 12(%esp), %ecx // Load count 42 movl 8(%esp), %edx // Load high 43 movl 4(%esp), %eax // Load low 44 45 testl $0x20, %ecx // If count >= 32 46 jnz 1f // goto 1 47 48 shrdl %cl, %edx, %eax // right shift low by count 49 shrl %cl, %edx // right shift high by count 50 ret 51 52 1: movl %edx, %eax // Move high to low 53 xorl %edx, %edx // clear high 54 shrl %cl, %eax // shift low by count - 32 55 ret 56 END_COMPILERRT_FUNCTION(__lshrdi3) 57 58 #endif // __SSE2__ 59 #endif // __i386__ 60 61 NO_EXEC_STACK_DIRECTIVE 62 63
