mmx

Let me preface this with.. I have extremely limited experience with ASM, and even less with SIMD. But it happens that I have the following MMX/SSE optimised code, that I would like to port across to AltiVec instructions for use on PPC/Cell processors. This is probably a big ask.. Even though it's only a few lines of code, I've had no end of trouble trying to work out what's going on here. The original function: static inline int convolve(const short *a, const short *b, int n) { int out = 0; union { __m64 m64; int i32[2]; } tmp; tmp.i32[0] = 0; tmp.i32[1] = 0; while (n >= 4) { tmp.m64 = _mm_add

What is the proper way to convert an __int64 value to an __m64 value for use with SSE? With gcc you can just use _mm_set_pi64x : #include <mmintrin.h> __int64 i = 0x123456LL; __m64 v = _mm_set_pi64x(i); Note that not all compilers have _mm_set_pi64x defined in mmintrin.h . For gcc it's defined like this: extern __inline __m64 __attribute__((__gnu_inline__, __always_inline__, __artificial__)) _mm_set_pi64x (long long __i) { return (__m64) __i; } which suggests that you could probably just use a cast if you prefer, e.g. __int64 i = 0x123456LL; __m64 v = (__m64)i; Failing that, if you're stuck

I'm currently learning assembly programming on Intel x86 processor. Could someone please explain to me, what is the difference between MMX and XMM register? I'm very confused in terms of what functions they serve and the difference and similarities between them? MM registers are the registers used by the MMX instruction set, one of the first attempts to add (integer-only) SIMD to x86. They are 64 bit wide and they are actually aliases for the mantissa parts of the x87 registers (but they are not affected by the FPU top of the stack position); this was done to keep compatibility with existing

Where can I find information about common SIMD tricks? I have an instruction set and know, how to write non-tricky SIMD code, but I know, SIMD now is much more powerful. It can hold complex conditional branchless code. For example ( ARMv6 ), the following sequence of instructions sets each byte of Rd equal to the unsigned minimum of the corresponding bytes of Ra and Rb: USUB8 Rd, Ra, Rb SEL Rd, Rb, Ra Links to tutorials / uncommon SIMD techniques are good too :) ARMv6 is the most interesting for me, but x86 (SSE,...)/ Neon (in ARMv7)/others are good too. One of the best SIMD resources ever was