Coherent4.2.10/i386/lib/repeat.inc
/ This file encapsulates a tentative change made to deal with potential
/ motherboard problems with use of the REP instruction prefix in conjunction
/ with the x86 I/O instructions; due to PC bus timing problems, some
/ peripheral boards may be unable to supply data within the required bus
/ times. It may be that using a LOOP instruction rather than a REP prefix
/ may help with this.
/
/ In the absence of real diagnostic tools to analyse this problem, here we
/ provide a macro which expands to either form so we can build kernels for
/ experimental purposes.
/ Use "-D_USE_REP_PREFIX=1" to compile for the REP mode,
/ and nothing to compile for the LOOP mode.
repeat .macro instr
.if .defined _USE_REP_PREFIX
rep
instr
.else
repeat_\.macno:
instr
loop repeat_\.macno
.endi
.endm