11d4c08d7
Denys Vlasenko
2025-07-09
Subject
libbb/bitops.c: add inlining comment
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libbb/bitops.c+20 -0
| @@ -58,6 +58,26 @@ void FAST_FUNC xorbuf16_aligned_long(void *dst, const void *src) | |
| # endif | |
| #endif | |
| } | |
| + | // The above can be inlined in libbb.h, in a way where compiler |
| + | // is even free to use better addressing modes than (%reg), and |
| + | // to keep the result in a register |
| + | // (to not store it to memory after each XOR): |
| + | //#if defined(__SSE__) |
| + | //#include <xmmintrin.h> |
| + | //^^^ or just: typedef float __m128_u attribute((__vector_size__(16),__may_alias__,__aligned__(1))); |
| + | //static ALWAYS_INLINE void xorbuf16_aligned_long(void *dst, const void *src) |
| + | //{ |
| + | // __m128_u xmm0, xmm1; |
| + | // asm volatile( |
| + | //"\n xorps %1,%0" |
| + | // : "=x" (xmm0), "=x" (xmm1) |
| + | // : "0" (*(__m128_u*)dst), "1" (*(__m128_u*)src) |
| + | // ); |
| + | // *(__m128_u*)dst = xmm0; // this store may be optimized out! |
| + | //} |
| + | //#endif |
| + | // but I don't trust gcc optimizer enough to not generate some monstrosity. |
| + | // See GMULT() function in TLS code as an example. |
| void FAST_FUNC xorbuf64_3_aligned64(void *dst, const void *src1, const void *src2) | |
| { | |