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More precise DELAY function.

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phil 1996-03-11 22:50:17 +00:00
parent 94fc5cf4ce
commit 26ee503b71
1 changed files with 27 additions and 1 deletions
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28
sys/arch/pc532/pc532/locore.s
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@ -1,4 +1,4 @@
/* $NetBSD: locore.s,v 1.33 1996/02/02 20:05:21 mycroft Exp $ */
/* $NetBSD: locore.s,v 1.34 1996/03/11 22:50:17 phil Exp $ */
/*
* Copyright (c) 1993 Philip A. Nelson.
@ -140,6 +140,32 @@ ENTRY(proc_trampoline)
/*****************************************************************************/
/*
* Burn N microseconds in a delay loop.
*/
ENTRY(delay) /* bsr 2 cycles; 80 ns */
cmpqd 0,S_ARG0 /* 2 cycles; 80 ns */
beq 2f /* 2 cycles; 80 ns */
movd S_ARG0,r0 /* 2 cycles; 80 ns */
acbd -1,r0,0f /* 5 cycles; 200 ns */
/* ====== */
/* 520 ns */
nop; nop; nop; nop /* 8 cycles; 320 ns */
ret 0 /* 4 cycles; 160 ns */
/* ====== */
/* 1000 ns */
/* 520 ns */
0: nop; nop; nop; nop /* 8 cycles; 320 ns */
/* ====== */
/* 840 ns */
1: nop; nop; nop; nop; nop /* 10 cycles; 400 ns */
nop; nop: nop: nop; nop /* 10 cycles; 400 ns */
acbd -1,r0,1b /* 5 cycles; 200 ns */
2: ret 0 /* 4 cycles; 160 ns */
/*****************************************************************************/
/*
* Signal trampoline; copied to top of user stack.
*/