binutils-gdb/sim/h8300/perifs.c
Steve Chamberlain 62b66d6df1 checkpoint
1993-01-18 20:24:47 +00:00

79 lines
1.6 KiB
C

/* Fake peripherals for the H8/330 */
#include "state.h"
perifs( )
/* This routine is called every few instructions to see if some sort
of hardware event is needed */
{
int interrupt = 0;
int lval;
int tmp;
/* What to do about the 16 bit timer */
/* Free running counter same as reg a */
if (saved_state.reg[OCRA] == saved_state.reg[FRC])
{
/* Set the counter A overflow bit */
saved_state.reg[TCSR] |= OCFA;
if (saved_state.reg[TCSR] & CCLRA)
{
saved_state.reg[FRC] = 0;
}
if (saved_state.reg[TIER] & OCIEA)
{
interrupt = 16;
}
}
/* Free running counter same as reg b */
if (saved_state.reg[OCRB] == saved_state.reg[FRC])
{
saved_state.reg[TCSR] |= OCFB;
if (saved_state.reg[TIER] & OCIEB)
{
interrupt = 17;
}
}
/* inc free runnning counter */
saved_state.reg[FRC]++;
if (saved_state.reg[FRC] == 0)
{
/* Must have overflowed */
saved_state.reg[TCSR] |= OVF;
if (BYTE_MEM(TIER) & OVIE)
interrupt = 18;
}
/* If we've had an interrupt and the bit is on */
if (interrupt && saved_state.ienable)
{
int ccr;
saved_state.ienable = 0;
ccr = saved_state.reg[CCR];
lval = WORD_MEM((interrupt)<<1);
lval = WORD_MEM(lval);
{
/* Push PC */
saved_state.reg[7] -= 2;
tmp = saved_state.reg[7];
SET_WORD_MEM (tmp, saved_state.reg[PC]);
/* Push CCR twice */
saved_state.reg[7] -=2 ;
tmp = saved_state.reg[7];
SET_BYTE_MEM(tmp,ccr);
SET_BYTE_MEM(tmp+1,ccr);
/* Set pc to point to first instruction of i vector */
saved_state.reg[PC] = lval;
}
}
}