signal bit operation

signal bit operation

 include/linux/signal.h

#define _SIG_SET_BINOP(name, op) \
static inline void name(sigset_t *r, const sigset_t *a, const sigset_t *b) \

{ \

unsigned long a0, a1, a2, a3, b0, b1, b2, b3; \

\

switch (_NSIG_WORDS) { \

case 4: \

a3 = a->sig[3]; a2 = a->sig[2]; \

b3 = b->sig[3]; b2 = b->sig[2]; \

r->sig[3] = op(a3, b3); \

r->sig[2] = op(a2, b2); \

case 2: \

a1 = a->sig[1]; b1 = b->sig[1]; \

r->sig[1] = op(a1, b1); \

case 1: \

a0 = a->sig[0]; b0 = b->sig[0]; \

r->sig[0] = op(a0, b0); \

break; \

default: \

BUILD_BUG(); \

} \

}

 

 

#define _sig_or(x,y) ((x) | (y))

_SIG_SET_BINOP(sigorsets, _sig_or)

#define _sig_and(x,y) ((x) & (y))

_SIG_SET_BINOP(sigandsets, _sig_and)

#define _sig_andn(x,y) ((x) & ~(y))

_SIG_SET_BINOP(sigandnsets, _sig_andn)

 

sigandnsets(d,s1,s2)

d = s1 & ~s2