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55 lines
2.1 KiB
C
55 lines
2.1 KiB
C
#ifndef COSMOPOLITAN_LIBC_INTRIN_PALIGNR_H_
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#define COSMOPOLITAN_LIBC_INTRIN_PALIGNR_H_
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#include "libc/assert.h"
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#include "libc/intrin/macros.h"
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#include "libc/macros.h"
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#include "libc/str/str.h"
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#if !(__ASSEMBLER__ + __LINKER__ + 0)
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void pvalignr(void *, const void *, const void *, size_t);
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/**
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* Overlaps vectors.
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*
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* 𝑖= 0 means 𝑐←𝑎
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* 0<𝑖<16 means 𝑐←𝑎║𝑏
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* 𝑖=16 means 𝑐←𝑏
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* 16<𝑖<32 means 𝑐←𝑏║0
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* 𝑖≥32 means 𝑐←0
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*
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* @param 𝑖 needs to be a literal, constexpr, or embedding
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* @see pvalignr()
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* @mayalias
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*/
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static void palignr(void *c, const void *b, const void *a, size_t i) {
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char t[48];
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memcpy(t, a, 16);
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memcpy(t + 16, b, 16);
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memset(t + 32, 0, 16);
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memcpy(c, t + MIN(32, i), 16);
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}
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#ifndef __STRICT_ANSI__
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#define palignr(C, B, A, I) \
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do { \
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if (!IsModeDbg() && X86_NEED(SSE) && X86_HAVE(SSSE3)) { \
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__intrin_xmm_t *Xmm0 = (void *)(C); \
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const __intrin_xmm_t *Xmm1 = (const __intrin_xmm_t *)(B); \
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const __intrin_xmm_t *Xmm2 = (const __intrin_xmm_t *)(A); \
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if (!X86_NEED(AVX)) { \
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asm("palignr\t%2,%1,%0" \
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: "=x"(*Xmm0) \
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: "x"(*Xmm2), "i"(I), "0"(*Xmm1)); \
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} else { \
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asm("vpalignr\t%3,%2,%1,%0" \
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: "=x"(*Xmm0) \
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: "x"(*Xmm1), "x"(*Xmm2), "i"(I)); \
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} \
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} else { \
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palignr(C, B, A, I); \
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} \
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} while (0)
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#endif
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#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
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#endif /* COSMOPOLITAN_LIBC_INTRIN_PALIGNR_H_ */
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