paul kelly longwordesatclearie john gay wrote looking things isaid pgcc site seem updated least year also looking gcc 31 series might better pgcc patches written gcc good better pgcc quite pgcc written back days gcc splintered due perception slow progress main branch number linux distributions wound using egcs partly derived pgcc work recall happiness restored world gcc 295 later bottom line pentiums better instruction sets original 386 instructions still support really instruction consequence gcc anyway since i386 cmov introduced pentium pro gcc 295 use instruction directed marchpentiumpro generally get percent improvement code compiled option fail pentium earlier processors pentium also started introducing pipelining properly generated code upto 30 faster equivulent code performs function thats art instruction scheduling rearranging instructions generated compiler make best use parallel superscalar pipelines present modern cpu gcc 295 fair go scheduling according mcpupentiumpentiumpro option gcc 31 better job fine tunes processors athlon athlonxp theyre process replacing compilers instruction scheduling whole new mechanism even better job thats ways road yet gcc 33 exotic extra instructions sets gcc 31 make use sse sse2 instructions instead 387 instructions use mfpmathsse option may see speed benefit theres chance may also see incompatibilities gcc still use i387 code missing functionality sse instruction set double precision floats example afaik current gcc ever use mmx 3dnow instructions though gcc 31 enables user code explicitly generate instructions c code kernel sometimes uses instruction sets get superfast block copies memory raid math much else sure improvements p4 introduce think mostly speed improvements rather execution changes p4 introduced sse2 _much_ improved version sse viable replacement i387 fpu code sse supports single precision floats sse2 handle doubles mmx sse shared registers fpu hobbles bit sse2 large dedicated register file far p4 cpu equipped sse2 amds x8664 cpus said well course x8664 whole ball game paul irish linux users group iluglinuxie httpwwwlinuxiemailmanlistinfoilug unsubscription information list maintainer listmasterlinuxie sun 28 jul 2002 034150 0100 ilug optimizing pentium pt2