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#include "../plan9/lib.h"
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#include "../plan9/sys9.h"
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#include <signal.h>
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#include <setjmp.h>
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/* A stack to hold pcs when signals nest */
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#define MAXSIGSTACK 20
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typedef struct Pcstack Pcstack;
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static struct Pcstack {
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	int sig;
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	void (*hdlr)(int, char*, Ureg*);
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	unsigned long restorepc;
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	Ureg *u;
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} pcstack[MAXSIGSTACK];
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static int nstack = 0;
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static void notecont(Ureg*, char*);
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void
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_notetramp(int sig, void (*hdlr)(int, char*, Ureg*), Ureg *u)
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{
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	Pcstack *p;
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	if(nstack >= MAXSIGSTACK)
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		_NOTED(1);	/* nesting too deep; just do system default */
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	p = &pcstack[nstack];
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	p->restorepc = u->pc;
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	p->sig = sig;
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	p->hdlr = hdlr;
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	p->u = u;
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	nstack++;
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	u->pc = (unsigned long) notecont;
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	_NOTED(2);	/* NSAVE: clear note but hold state */
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}
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static void
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notecont(Ureg *u, char *s)
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{
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	Pcstack *p;
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	void(*f)(int, char*, Ureg*);
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	p = &pcstack[nstack-1];
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	f = p->hdlr;
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	u->pc = p->restorepc;
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	nstack--;
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	(*f)(p->sig, s, u);
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	_NOTED(3);	/* NRSTR */
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}
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#define JMPBUFPC 1
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#define JMPBUFSP 0
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extern sigset_t	_psigblocked;
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void
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siglongjmp(sigjmp_buf j, int ret)
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{
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	struct Ureg *u;
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	if(j[0])
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		_psigblocked = j[1];
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	if(nstack == 0 || pcstack[nstack-1].u->sp > j[2+JMPBUFSP])
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		longjmp(j+2, ret);
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	u = pcstack[nstack-1].u;
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	nstack--;
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	u->ax = ret;
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	if(ret == 0)
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		u->ax = 1;
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	u->pc = j[2+JMPBUFPC];
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	u->sp = j[2+JMPBUFSP] + 4;
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	_NOTED(3);	/* NRSTR */
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}