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#include <u.h>
#include <libc.h>
enum
{
Pagesize = 4096,
Semperpg = Pagesize/(16*sizeof(uint)),
Lockaddr = 0x60000000,
POWER = 0x320,
MAGNUM = 0x330,
MAGNUMII = 0x340,
R4K = 0x500,
};
static int arch;
extern int C_3ktas(int*);
extern int C_4ktas(int*);
extern int C_fcr0(void);
static void
lockinit(void)
{
void *v;
if(arch != 0)
return; /* allow multiple calls */
arch = C_fcr0();
switch(arch) {
case POWER:
v = (void*)Lockaddr;
if(segattach(SG_CEXEC, "lock", v, Pagesize) == (void*)-1) {
arch = MAGNUM;
break;
}
memset(v, 0, Pagesize);
break;
case MAGNUM:
case MAGNUMII:
case R4K:
break;
default:
arch = R4K;
break;
}
}
void
lock(Lock *lk)
{
int *hwsem;
int hash;
retry:
switch(arch) {
case 0:
lockinit();
goto retry;
case MAGNUM:
case MAGNUMII:
while(C_3ktas(&lk->val))
sleep(0);
return;
case R4K:
for(;;){
while(lk->val)
;
if(C_4ktas(&lk->val) == 0)
return;
}
break;
case POWER:
/* Use low order lock bits to generate hash */
hash = ((int)lk/sizeof(int)) & (Semperpg-1);
hwsem = (int*)Lockaddr+hash;
for(;;) {
if((*hwsem & 1) == 0) {
if(lk->val)
*hwsem = 0;
else {
lk->val = 1;
*hwsem = 0;
return;
}
}
while(lk->val)
;
}
}
}
int
canlock(Lock *lk)
{
int *hwsem;
int hash;
retry:
switch(arch) {
case 0:
lockinit();
goto retry;
case MAGNUM:
case MAGNUMII:
if(C_3ktas(&lk->val))
return 0;
return 1;
case R4K:
if(C_4ktas(&lk->val))
return 0;
return 1;
case POWER:
/* Use low order lock bits to generate hash */
hash = ((int)lk/sizeof(int)) & (Semperpg-1);
hwsem = (int*)Lockaddr+hash;
if((*hwsem & 1) == 0) {
if(lk->val)
*hwsem = 0;
else {
lk->val = 1;
*hwsem = 0;
return 1;
}
}
break;
}
return 0;
}
void
unlock(Lock *lk)
{
lk->val = 0;
}
int
_tas(int *p)
{
int *hwsem;
int hash;
retry:
switch(arch) {
case 0:
lockinit();
goto retry;
case MAGNUM:
case MAGNUMII:
return C_3ktas(p);
case R4K:
return C_4ktas(p);
case POWER:
/* Use low order lock bits to generate hash */
hash = ((int)p/sizeof(int)) & (Semperpg-1);
hwsem = (int*)Lockaddr+hash;
if((*hwsem & 1) == 0) {
if(*p)
*hwsem = 0;
else {
*p = 1;
*hwsem = 0;
return 0;
}
}
break;
}
return 1;
}
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