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Article #3614Re: 386 Assembler Question - Easy one...
From: David Meltzer
Date: Thu, 12 Nov 1992 04:07
Date: Thu, 12 Nov 1992 04:07
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In article <1992Nov11.114831.6643@ufhx1.ufh.ac.za> cssjs2@ufhx1.ufh.ac.za (Mr I Scheepers) writes: >In <1992Nov9.162931.1@camins.camosun.bc.ca> morley@camins.camosun.bc.ca writes: >>In 386 assembler I need to fill an extended register with 4 copies >>of the same byte. Right now I'm using the following: > >> mov al,VALUE >> mov ah,VALUE >> shl eax,16 >> mov al,VALUE >> mov ah,VALUE > >>I'm curious... is there a better/faster way to stuff the register? > >How about: > mov al,VALUE > mov ah,al > mov eax,ax Wouldnt't that last line move the 16-bit value of AX register to the 32-bit EAX register, like doing a mov ax,al? Unfortunately there is no way to access the high 16-bits of EAX directly as such, like a EHAX (which would invariably lead to a EHAL <sigh>). David Meltzer ,
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Newsgroups: comp.os.msdos.programmer Path: arc1-ca.pugleaf.net!sparky!uunet!spool.mu.edu!uwm.edu!rpi!psinntp!psinntp!newstand.syr.edu!erc.cat.syr.edu!dmeltzer From: dmeltzer@erc.cat.syr.edu (David Meltzer) Subject: Re: 386 Assembler Question - Easy one... Message-ID: <1992Nov11.230733.4638@newstand.syr.edu> Organization: Electronic Resource Center, Syracuse References: <1992Nov9.162931.1@camins.camosun.bc.ca> <1992Nov11.114831.6643@ufhx1.ufh.ac.za> Date: Wed, 11 Nov 92 23:07:33 EST Lines: 23