#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 voidlockinit(void){	int n; 	if(arch != 0)		return;	/* allow multiple calls */	arch = C_fcr0();	switch(arch) {	case POWER:		n = segattach(SG_CEXEC, "lock", (void*)Lockaddr, Pagesize);		if(n < 0) {			arch = MAGNUM;			break;		}		memset((void*)Lockaddr, 0, Pagesize);		break;	case MAGNUM:	case MAGNUMII:	case R4K:		break;	default:		arch = R4K;		break;	}	} voidlock(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)				;		}	}	} intcanlock(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;			}		}		return 0;	}	} voidunlock(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;			}		}		return 1;	}	}