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Refactor bus reads and writes to split common code.

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This commit is contained in:
Radosław Kujawa 2017-02-25 12:54:15 +01:00
parent 1f072e1b11
commit edab91de3f
1 changed files with 36 additions and 28 deletions
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64
src/bus.c
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@ -16,6 +16,8 @@
#define RK65C02_BUS_SIZE 64*1024
static void bus_access_device(bus_t *, uint16_t, device_t **, uint16_t *);
void
bus_device_add(bus_t *b, device_t *d, uint16_t addr)
{
@ -43,58 +45,64 @@ bus_device_dump(bus_t *b)
}
}
uint8_t
bus_read_1(bus_t *t, uint16_t addr)
/*
* Determine which device is accessed and at what offset. The d argument is
* filled with pointer to accessed device, off with offset.
* Returns device NULL when hitting unmapped space.
*/
static void
bus_access_device(bus_t *t, uint16_t addr, device_t **d, uint16_t *off)
{
uint8_t val;
uint16_t doff;
device_mapping_t *dm;
device_t *dtmp, *d;
device_t *dtmp;
d = NULL;
*d = NULL;
LL_FOREACH(t->dm_head, dm) {
dtmp = dm->dev;
if ( (addr >= dm->addr) && (addr < (dm->addr + dtmp->size)) ) {
d = dtmp;
*d = dtmp;
doff = dm->addr;
}
}
if (d == NULL) {
if (*d == NULL) {
fprintf(stderr, "Hitting unmapped bus space @ %x!", addr);
return 0xFF;
return;
}
val = d->read_1(d, addr - doff);
*off = addr - doff;
}
printf("bus READ @ %x (off %x) value %x\n", addr, addr - doff, val);
uint8_t
bus_read_1(bus_t *t, uint16_t addr)
{
uint8_t val;
uint16_t off;
device_t *d;
bus_access_device(t, addr, &d, &off);
if (d == NULL)
return 0xFF;
else
val = d->read_1(d, off);
printf("bus READ @ %x (off %x) value %x\n", addr, off, val);
return val;
}
void
bus_write_1(bus_t *t, uint16_t addr, uint8_t val)
{
uint16_t doff;
device_mapping_t *dm;
device_t *dtmp, *d;
uint16_t off;
device_t *d;
d = NULL;
bus_access_device(t, addr, &d, &off);
LL_FOREACH(t->dm_head, dm) {
dtmp = dm->dev;
if ( (addr >= dm->addr) && (addr < (dm->addr + dtmp->size)) ) {
d = dtmp;
doff = dm->addr;
}
}
if (d == NULL) {
fprintf(stderr, "Hitting unmapped bus space @ %x!", addr);
}
printf("bus WRITE @ %x (off %x) value %x\n", addr, addr - doff, val);
d->write_1(d, addr - doff, val);
printf("bus WRITE @ %x (off %x) value %x\n", addr, off, val);
d->write_1(d, off, val);
}
bus_t