;-------------------------------------------------------------------------------- ; Title : Peek_byte_vax.mar ; Author : Neil S. Rieck (Kitchener/Waterloo/Cambridge, Ontario, Canada) ; Created: 1999.11.12 ; ; Notes: ; 1. This VAX assembly language function peeks (byte wise) into a memory location ; 2. It is tested for use with VAX-BASIC (see peek_demo1.bas) ; 3. parameters are passed here via register ap (argument pointer) a.k.a. r12 ; 4. results are returned via r0 (and sometimes r1) ;-------------------------------------------------------------------------------- .entry peek_byte_vax,^M<> ; function name is PEEK_BYTE_VAX (null entry mask) clrq r0 ; clear both r0 + r1 (cuz q = 64 bit) movl @4(ap),r2 ; passed parameter #1 is address of data movb (r2),r0 ; do an indirect byte fetch into r0 ret ; return to calling program .end
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Neil Rieck
Kitchener - Waterloo - Cambridge, Ontario, Canada.