| 1 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 2 | // See https://llvm.org/LICENSE.txt for license information. |
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| 3 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 4 | |
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| 5 | #include "../assembly.h" |
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| 6 | |
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| 7 | // di_int __lshrdi3(di_int input, int count); |
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| 8 | |
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| 9 | // This routine has some extra memory traffic, loading the 64-bit input via two |
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| 10 | // 32-bit loads, then immediately storing it back to the stack via a single 64-bit |
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| 11 | // store. This is to avoid a write-small, read-large stall. |
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| 12 | // However, if callers of this routine can be safely assumed to store the argument |
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| 13 | // via a 64-bt store, this is unnecessary memory traffic, and should be avoided. |
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| 14 | // It can be turned off by defining the TRUST_CALLERS_USE_64_BIT_STORES macro. |
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| 15 | |
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| 16 | #ifdef __i386__ |
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| 17 | #ifdef __SSE2__ |
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| 18 | |
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| 19 | .text |
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| 20 | .balign 4 |
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| 21 | DEFINE_COMPILERRT_FUNCTION(__lshrdi3) |
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| 22 | movd 12(%esp), %xmm2 // Load count |
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| 23 | #ifndef TRUST_CALLERS_USE_64_BIT_STORES |
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| 24 | movd 4(%esp), %xmm0 |
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| 25 | movd 8(%esp), %xmm1 |
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| 26 | punpckldq %xmm1, %xmm0 // Load input |
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| 27 | #else |
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| 28 | movq 4(%esp), %xmm0 // Load input |
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| 29 | #endif |
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| 30 | psrlq %xmm2, %xmm0 // shift input by count |
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| 31 | movd %xmm0, %eax |
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| 32 | psrlq $32, %xmm0 |
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| 33 | movd %xmm0, %edx |
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| 34 | ret |
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| 35 | END_COMPILERRT_FUNCTION(__lshrdi3) |
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| 36 | |
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| 37 | #else // Use GPRs instead of SSE2 instructions, if they aren't available. |
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| 38 | |
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| 39 | .text |
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| 40 | .balign 4 |
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| 41 | DEFINE_COMPILERRT_FUNCTION(__lshrdi3) |
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| 42 | movl 12(%esp), %ecx // Load count |
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| 43 | movl 8(%esp), %edx // Load high |
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| 44 | movl 4(%esp), %eax // Load low |
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| 45 | |
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| 46 | testl $0x20, %ecx // If count >= 32 |
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| 47 | jnz 1f // goto 1 |
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| 48 | |
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| 49 | shrdl %cl, %edx, %eax // right shift low by count |
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| 50 | shrl %cl, %edx // right shift high by count |
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| 51 | ret |
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| 52 | |
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| 53 | 1: movl %edx, %eax // Move high to low |
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| 54 | xorl %edx, %edx // clear high |
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| 55 | shrl %cl, %eax // shift low by count - 32 |
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| 56 | ret |
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| 57 | END_COMPILERRT_FUNCTION(__lshrdi3) |
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| 58 | |
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| 59 | #endif // __SSE2__ |
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| 60 | #endif // __i386__ |
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| 61 | |
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| 62 | NO_EXEC_STACK_DIRECTIVE |
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| 63 | |
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| 64 | |
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