Post a Comment On: cbloom rants

Finnish was perhaps the fastest (non-nop) compressor in the world around 1995 (? not sure on the exact year. Definitely before P-Pro and CMOV and branch penalties and such; this is a pre-Pentium-era optimized compressor; it definitely existed before LZP1 (1996) since it was one of the things I benchmarked against). (heck it might be a 286-era compressor, seeing as it's all 16-bit!) Finnish was by some guys that I assume were from Finland. If anybody knows the correct attribution please let me know. I was thinking about it the other day because we talked about the old segment register trick that we used to do, and I always thought this was such a neat little bit of code. It also uses the byte-regs as part of word-reg tricks. Finnish : ; es = CharTable ; bx = hash index ; dl = control bits ; ds[si] = input ; ds[di] = output ; ax/al/ah = input char ; bp = control ptr ProcessByte macro SourceReg,BitVal cmp SourceReg, es:[bx] je ProcessByte_done or dl, BitVal mov es:[bx], SourceReg mov ds:[di], SourceReg inc di ProcessByte_done: mov bh, bl mov bl, SourceReg endm ProcessBlockLoop: mov bp, di ; ControlPtr = CompPtr++; inc di xor dl, dl ; Control = 0; lodsw ; AX = ds[si] , si += 2 ProcessByte al, 80h ProcessByte ah, 40h lodsw ProcessByte al, 20h ProcessByte ah, 10h lodsw ProcessByte al, 08h ProcessByte ah, 04h lodsw ProcessByte al, 02h ProcessByte ah, 01h mov ds:[bp], dl ; *ControlPtr = Control