I would like to say this manual code writing optimization may be mostly done by compiler's optimization work, so one may view these changes as unnecessary, but I think it's not the execute to do not blame the code.
在 2013-04-11四的 14:31 +0800，li guang写道： > this patch-set is v2 of previous 'translate: cleanup > gen_intermediate_code_internal patch' > > v2: Keep variable 'num_insns' initailization > spotted by 陳韋任 (Wei-Ren Chen) <che...@iis.sinica.edu.tw> > update: > 1. correct miss-spelled word 'mini*ally' > 2. change second place just like first > > here are instructions in the finial qemu-system-x86 > before and after my chanage, you can easily find a > redundant 'addl' was removed > > before change: > > 38c415: 3b 45 d4 cmp -0x2c(%ebp),%eax > 38c418: 7d 23 jge 38c43d > <gen_intermediate_code_internal+0x58f> > ------------------------------------------------------------------ > 38c41a: 83 45 d0 01 addl $0x1,-0x30(%ebp) > ------------------------------------------------------------------ > 38c41e: eb 15 jmp 38c435 > <gen_intermediate_code_internal+0x587> > 38c420: 8b 45 d0 mov -0x30(%ebp),%eax > 38c423: 8b 93 48 15 00 00 mov 0x1548(%ebx),%edx > 38c429: c6 84 02 a8 0e 01 00 movb $0x0,0x10ea8(%edx,%eax,1) > 38c430: 00 > 38c431: 83 45 d0 01 addl $0x1,-0x30(%ebp) > 38c435: 8b 45 d0 mov -0x30(%ebp),%eax > 38c438: 3b 45 d4 cmp -0x2c(%ebp),%eax > 38c43b: 7c e3 jl 38c420 > <gen_intermediate_code_internal+0x572> > > > after change: > > 38c415: 3b 45 d4 cmp -0x2c(%ebp),%eax > 38c418: 7d 1f jge 38c439 > <gen_intermediate_code_internal+0x58b> > 38c41a: eb 11 jmp 38c42d > <gen_intermediate_code_internal+0x57f> > 38c41c: 8b 45 d0 mov -0x30(%ebp),%eax > 38c41f: 8b 93 48 15 00 00 mov 0x1548(%ebx),%edx > 38c425: c6 84 02 a8 0e 01 00 movb $0x0,0x10ea8(%edx,%eax,1) > 38c42c: 00 > 38c42d: 83 45 d0 01 addl $0x1,-0x30(%ebp) > 38c431: 8b 45 d0 mov -0x30(%ebp),%eax > 38c434: 3b 45 d4 cmp -0x2c(%ebp),%eax > 38c437: 7c e3 jl 38c41c > <gen_intermediate_code_internal+0x56e> > > >
