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#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "../port/error.h"
#include "ureg.h"
extern int (*breakhandler)(Ureg *ur, Proc*); /* trap.c */
extern Instr BREAK; /* trap.c */
extern void portbreakinit(void);
#define getop(i) ((i>>26)&0x3F)
#define getxo(i) ((i>>1)&0x3FF)
#define getbobi(i) bo = (i>>21)&0x1f; bi = (i>>16)&0x1f; xx = (i>>11)&0x1f;
void
machbreakinit(void)
{
portbreakinit();
breakhandler = breakhit;
}
Instr
machinstr(ulong addr)
{
if (addr < KTZERO)
error(Ebadarg);
return *(Instr*)addr;
}
void
machbreakset(ulong addr)
{
if (addr < KTZERO)
error(Ebadarg);
*(Instr*)addr = BREAK;
segflush((void*)addr, sizeof(Instr));
}
void
machbreakclear(ulong addr, Instr i)
{
if (addr < KTZERO)
error(Ebadarg);
*(Instr*)addr = i;
segflush((void*)addr, sizeof(Instr));
}
static int
condok(Ureg *ur, ulong ir, int ctrok)
{
int bo, bi, xx;
ulong ctrval;
ctrval = ur->ctr;
getbobi(ir);
if(xx)
return 0; /* illegal */
if((bo & 0x4) == 0) {
if(!ctrok)
return 0; /* illegal */
ctrval--;
}
if(bo & 0x4 || (ctrval!=0)^((bo>>1)&1)) {
if(bo & 0x10 || (((ur->cr & (1L<<(31-bi))!=0)==((bo>>3)&1))))
return 1;
}
return 0;
}
/*
* Return the address of the instruction that will be executed after the
* instruction at ur->pc, accounting for current branch conditions.
*/
ulong
machnextaddr(Ureg *ur)
{
long imm;
ulong ir;
ir = *(ulong*)ur->pc;
switch(getop(ir)) {
case 18: /* branch */
imm = ir & 0x03FFFFFC;
if(ir & 0x02000000)
imm |= 0xFC000000; /* sign extended */
if((ir & 2) == 0) /* relative address */
return ur->pc + imm;
return imm;
case 16: /* conditional branch */
if(condok(ur, ir&0xFFFF0000, 1)){
imm = ir & 0xFFFC;
if(ir & 0x08000)
imm |= 0xFFFF0000; /* sign extended */
if((ir & 2) == 0) /* relative address */
return ur->pc + imm;
return imm;
}
break;
case 19: /* conditional branch to register */
switch(getxo(ir)){
case 528: /* bcctr */
if(condok(ur, ir, 0))
return ur->ctr & ~3;
break;
case 16: /* bclr */
if(condok(ur, ir, 1))
return ur->lr & ~3;
break;
}
break;
}
return ur->pc+4; /* next instruction */
}
int
isvalid_va(void *v)
{
return (ulong)v >= KTZERO;
}
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