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#include <u.h>
#include <libc.h>
#include "dat.h"
#include "fns.h"
static Segment *
seglook(u32int a, int n, u32int **lp)
{
Segment *s;
for(s = segs; s < segs + nelem(segs); s++)
if(a >= s->start && a < s->start + s->size)
break;
if(s == segs + nelem(segs)) return nil;
if(a + n > s->start + s->size) return nil;
if(lp != nil) *lp = s->data + (a - s->start >> 2);
return s;
}
u8int
memread8(u32int a)
{
u32int *p;
if(seglook(a, 1, &p) == nil) sysfatal("invalid read from %.8ux (pc=%.8ux)", a, curpc);
switch(a & 3){
case 0: return *p;
case 1: return *p >> 8;
case 2: return *p >> 16;
case 3: return *p >> 24;
}
return 0;
}
u16int
memread16(u32int a)
{
u32int *p;
if(seglook(a, 2, &p) == nil) sysfatal("invalid read from %.8ux (pc=%.8ux)", a, curpc);
switch(a & 3){
case 0: return *p;
case 1: return *p >> 8;
case 2: return *p >> 16;
case 3: return *p >> 24 | p[1] << 8;
}
return 0;
}
u32int
memread32(u32int a)
{
u32int *p;
if(seglook(a, 4, &p) == nil) sysfatal("invalid read from %.8ux (pc=%.8ux)", a, curpc);
switch(a & 3){
case 0: return *p;
case 1: return *p >> 8 | p[1] << 24;
case 2: return *p >> 16 | p[1] << 16;
case 3: return *p >> 24 | p[1] << 8;
}
return *p;
}
void
memwrite(u32int a, u32int v, u32int m)
{
u32int *p;
Segment *s;
s = seglook(a, 4, &p);
if(s == nil || (s->flags & SEGRO) != 0) sysfatal("invalid write to %.8ux=%.8ux (mask=%.8ux, pc=%.8ux)", a, v, m, curpc);
*p = *p & ~m | v & m;
}
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