[LAD] How do you improve optimization for integer calculations?

Hello. I just have attempt, writing serious application, considering language (C), tookit (gtk3, cairo, pango, etc) and that it is audio app. Besides that many audio things use simple "float" for audio data, i noticed some posts, where tension towards integer math appeared. While it is not my case (my app is jack-based, and audio data have FP type everywhere), i slightly distracted from audio side. My app for now is spectrum analyzer, which later should evolve into couple of spectral editing helper utilities (more exactly to generate spectrogram and apply changes either by resynth or by filtering with diff spectrogram). I distracted to experiments with graphics post-processing for instant spectrum view rendering. Due to cairo nature, color data in cairo image surface may be at best argb32, rgb24 and rgb30 (for now i implemented uspport only for first two). As result post-processing is all done in integer mode. I can understand this, as i noticed that channel orders in memory depends on endianness, what points that cairo relies more on masks and bitshifts than for byte value arrays where is possible. I decided to look in debugger for how gcc does optimize these ops. Noticed following. Below is code chunk from kdbg with some asm blocks expanded. There is only one line, where i tried to use floating point ops, just for comparison (plus some context for better understanding). for (int l = 0; l < 3; l++) for (int c = 0; c < 3; c++) { unsigned char * p = bpix[l][c]; col[0] += p[0] , 0x5b27 movzbl 0x60(%rsp),%esi col[1] += p[1] , 0x5a34 movzbl 0x65(%rsp),%eax col[2] += p[2] , 0x5a42 movzbl 0x62(%rsp),%edx col[3] += p[3]; 0x5a47 movzbl 0x67(%rsp),%esi 0x5a4c mov 0x10(%rsp),%rbp } col[0] /= 9.0, col[1] /= 9.0, col[2] /= 9.0, col[3] /= 9.0; 0x5a39 pxor %xmm0,%xmm0 op[0] += col[0] , 0x5b8d add %sil,0x0(%rbp) op[1] += col[1] , 0x5b94 add %cl,0x1(%rbp) op[2] += col[2] , 0x5b97 add %dl,0x2(%rbp) op[3] += col[3]; 0x5b91 add %al,0x3(%rbp) for (int l = 0; l < 3; l++) ip[l] += 3; op += ch_n; } Notice, how line, containing chain of divisions, is compiled to single sse operation. What is interesting, this is only asm line, involving xmm or imm - i can't find anything else like mov, involving these registers. With division to integer 9 - it is still one line, but no xmm is involved. col[0] += p[0] , 0x5b17 movzbl 0x64(%rsp),%eax col[1] += p[1] , 0x5a35 movzbl 0x65(%rsp),%eax col[2] += p[2] , 0x5a4a movzbl 0x7e(%rsp),%esi col[3] += p[3]; 0x5a4f movzbl 0x7f(%rsp),%ecx } col[0] /= 9, col[1] /= 9, col[2] /= 9, col[3] /= 9; 0x5a3a mov $0x38e38e39,%r8d op[0] += col[0] , 0x5b78 add %dl,0x0(%rbp) op[1] += col[1] , 0x5b3a add %dil,0x1(%rbp) As for GCC opts, i used unusual combo "-march=native -O3 -g" in order to get exhausing optimization, but still keep it readable for kdbg disasm to get a look. While searching for info about sse integer support, search pointed me to wikipedia page about x86 instructions, where i found almost enough instruction set - logical, add, sub and mul, signed and unsigned, words and bytes (at least in SSE2 which according to description enabled MMX set to use SSE registers, where integer support was primary in MMX). So, i'm in maze - why doesn't gcc involve such ops in integer mode? Could it be possible, that what it did is better without SSE? I'm about to eventually try more FP ops in this place but unsure, about possible conversions, since source and dest are anyway cairo surfaces with integer data.