?? pc.c
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#/* *//* * PC-11 Paper tape reader/punch driver */#include "../param.h"#include "../conf.h"#include "../user.h"#define PCADDR 0177550#define CLOSED 0#define WAITING 1#define READING 2#define EOF 3#define RDRENB 01#define IENABLE 0100#define DONE 0200#define BUSY 04000#define ERROR 0100000#define PCIPRI 30#define PCOPRI 40#define PCOLWAT 50#define PCOHWAT 100#define PCIHWAT 250struct { int pcrcsr; int pcrbuf; int pcpcsr; int pcpbuf;};struct clist { int cc; int cf; int cl;};struct pc11 { int pcstate; struct clist pcin; struct clist pcout;} pc11;pcopen(dev, flag){ extern lbolt; if (flag==0) { if (pc11.pcstate!=CLOSED) { u.u_error = ENXIO; return; } pc11.pcstate = WAITING; while(pc11.pcstate==WAITING) { PCADDR->pcrcsr = IENABLE|RDRENB; sleep(&lbolt, PCIPRI); } } else { PCADDR->pcpcsr =| IENABLE; pcleader(); }}pcclose(dev, flag){ if (flag==0) { spl4(); while (getc(&pc11.pcin) >= 0); PCADDR->pcrcsr = 0; pc11.pcstate = CLOSED; spl0(); } else pcleader();}pcread(){ register int c; spl4(); do { while ((c = getc(&pc11.pcin)) < 0) { if (pc11.pcstate==EOF) goto out; if ((PCADDR->pcrcsr&(ERROR|BUSY|DONE))==0) PCADDR->pcrcsr =| IENABLE|RDRENB; sleep(&pc11.pcin, PCIPRI); } } while (passc(c)>=0);out: spl0();}pcwrite(){ register int c; while ((c=cpass())>=0) pcoutput(c);}pcstart(){ register int c; if (PCADDR->pcpcsr&DONE && (c = getc(&pc11.pcout)) >= 0) PCADDR->pcpbuf = c;}pcrint(){ if (pc11.pcstate==WAITING) { if (PCADDR->pcrcsr&ERROR) return; pc11.pcstate = READING; } if (pc11.pcstate==READING) { if (PCADDR->pcrcsr&ERROR) pc11.pcstate = EOF; else { putc(PCADDR->pcrbuf, &pc11.pcin); if (pc11.pcin.cc < PCIHWAT) PCADDR->pcrcsr =| IENABLE|RDRENB; } wakeup(&pc11.pcin); }}pcpint(){ pcstart(); if (pc11.pcout.cc <= PCOLWAT) wakeup(&pc11.pcout);}pcoutput(c){ if (PCADDR->pcpcsr&ERROR) { u.u_error = EIO; return; } if (pc11.pcout.cc >= PCOHWAT) sleep(&pc11.pcout, PCOPRI); putc(c, &pc11.pcout); spl4(); pcstart(); spl0();}pcleader(){ register int i; i = 100; do pcoutput(0); while (--i);}?? 快捷鍵說明
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