ref: 0c50e1bc3d63f8a62986bbd140f9aef48a0cb076
dir: /sys/src/ape/lib/ap/amd64/notetramp.c/
#include "../plan9/lib.h" #include "../plan9/sys9.h" #include <signal.h> #include <setjmp.h> /* A stack to hold pcs when signals nest */ #define MAXSIGSTACK 20 typedef struct Pcstack Pcstack; static struct Pcstack { int sig; void (*hdlr)(int, char*, Ureg*); unsigned long long restorepc; Ureg *u; } pcstack[MAXSIGSTACK]; static int nstack = 0; static void notecont(Ureg*, char*); void _notetramp(int sig, void (*hdlr)(int, char*, Ureg*), Ureg *u) { Pcstack *p; if(nstack >= MAXSIGSTACK) _NOTED(1); /* nesting too deep; just do system default */ p = &pcstack[nstack]; p->restorepc = u->pc; p->sig = sig; p->hdlr = hdlr; p->u = u; nstack++; u->pc = (unsigned long long) notecont; _NOTED(2); /* NSAVE: clear note but hold state */ } static void notecont(Ureg *u, char *s) { Pcstack *p; void(*f)(int, char*, Ureg*); p = &pcstack[nstack-1]; f = p->hdlr; u->pc = p->restorepc; nstack--; (*f)(p->sig, s, u); _NOTED(3); /* NRSTR */ } #define JMPBUFPC 1 #define JMPBUFSP 0 extern sigset_t _psigblocked; typedef struct { sigset_t set; sigset_t blocked; unsigned long long jmpbuf[2]; } sigjmp_buf_amd64; void siglongjmp(sigjmp_buf j, int ret) { struct Ureg *u; sigjmp_buf_amd64 *jb; jb = (sigjmp_buf_amd64*)j; if(jb->set) _psigblocked = jb->blocked; if(nstack == 0 || pcstack[nstack-1].u->sp > jb->jmpbuf[JMPBUFSP]) longjmp((void*)jb->jmpbuf, ret); u = pcstack[nstack-1].u; nstack--; u->ax = ret; if(ret == 0) u->ax = 1; u->pc = jb->jmpbuf[JMPBUFPC]; u->sp = jb->jmpbuf[JMPBUFSP] + 8; _NOTED(3); /* NRSTR */ }