mirror of
https://github.com/DoctorWkt/pdp7-unix.git
synced 2026-01-21 18:16:32 +00:00
817 lines
14 KiB
C
817 lines
14 KiB
C
// b.c - B compiler for PDP-7 Unix
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//
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// Implemented in a subset of the C language compatible with B.
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// Coding style and organization based on lastc1120c.c
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//
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// (C) 2016 Robert Swierczek, GPL3
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//
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// Just enough working to compile hello.b:
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// gcc -m32 -Wno-multichar b.c -o b
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// ./b hello.b hello.s
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// perl as7 --out a.out bl.s hello.s bi.s
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// perl a7out a.out
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#ifdef _WIN32
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#include <io.h>
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#else
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#include <unistd.h>
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#endif
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#include <stdio.h>
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#include <stdlib.h>
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#include <memory.h>
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#include <fcntl.h>
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#define eof xeof
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int fin = 0;
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int fout = 1;
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int symtab[500] = { /* class value name */
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1, 5,'a','u','t','o', 0 ,
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1, 6,'e','x','t','r','n', 0 ,
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1,10,'g','o','t','o', 0 ,
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1,11,'r','e','t','u','r','n', 0 ,
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1,12,'i','f', 0 ,
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1,13,'w','h','i','l','e', 0 ,
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1,14,'e','l','s','e', 0 ,
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};
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int ctab[] = {
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0,127,127,127, 0,127,127,127, /* NUL SOH STX ETX EOT ENQ ACK BEL */
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127,126,126,127,127,127,127,127, /* BS TAB LF VT FF CR SO SI */
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127,127,127,127,127,127,127,127, /* DLE DC1 DC2 DC3 DC4 NAK SYN ETB */
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127,127,127,127,127,127,127,127, /* CAN EM SUB ESC FS GS RS US */
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126, 34,122,127,127, 44, 47,121, /* SPC ! " # $ % & ' */
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6, 7, 42, 40, 9, 41,127, 43, /* ( ) * + , - . / */
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124,124,124,124,124,124,124,124, /* 0 1 2 3 4 5 6 7 */
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124,124, 8, 1, 63, 80, 65, 90, /* 8 9 : ; < = > ? */
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127,123,123,123,123,123,123,123, /* @ A B C D E F G */
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123,123,123,123,123,123,123,123, /* H I J K L M N O */
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123,123,123,123,123,123,123,123, /* P Q R S T U V W */
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123,123,123, 4,127, 5, 48,127, /* X Y Z [ \ ] ^ _ */
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127,123,123,123,123,123,123,123, /* ` a b c d e f g */
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123,123,123,123,123,123,123,123, /* h i j k l m n o */
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123,123,123,123,123,123,123,123, /* p q r s t u v w */
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123,123,123, 2, 48, 3,127,127, /* x y z { | } ~ DEL */
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};
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/* storage */
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int symbuf[10];
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int peeksym = -1;
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int peekc = 0;
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int eof = 0;
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int line = 1;
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int *csym = 0;
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int *ns;
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int cval = 0;
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int isn = 0;
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int nisn = 0;
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int nerror = 0;
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int nauto = 0;
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int main(int argc, char **argv) {
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if (argc > 1) {
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if (argc > 2) {
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if ((fout = creat(argv[2], 0777))<0) {
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error('fo');
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exit(1);
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}
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}
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if ((fin = open(argv[1],0))<0) {
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error('fi');
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exit(1);
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}
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}
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while (!eof) {
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ns = symtab + 51;
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extdef();
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blkend();
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}
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xflush();
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exit(nerror);
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}
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int *lookup() {
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int *np, *sp, *rp;
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rp = symtab;
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while (rp < ns) {
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np = rp + 2;
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sp = symbuf;
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while (*np==*sp) {
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if (!*np)
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return rp;
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np = np + 1;
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sp = sp + 1;
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}
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while (*np)
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np = np + 1;
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rp = np + 1;
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}
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sp = symbuf;
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if (ns >= symtab + 490) {
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error("sf");
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exit(1);
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}
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*ns = 0;
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ns[1] = 0;
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ns = ns + 2;
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while (*ns = *sp) {
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ns = ns + 1;
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sp = sp + 1;
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}
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ns = ns + 1;
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return rp;
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}
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symbol() {
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// extern peeksym, peekc, eof, xread, subseq, error, line;
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// extern *csym, symbuf[], namsiz, lookup[], ctab, cval;
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// auto b, c, ct;
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// char symbuf[], sp[], ctab[];
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int b, c, ct;
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int *sp;
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if (peeksym>=0) {
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c = peeksym;
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peeksym = -1;
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return(c);
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}
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if (peekc) {
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c = peekc;
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peekc = 0;
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} else {
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if (eof)
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return(0);
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else
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c = xread();
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}
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loop:
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ct = ctab[c];
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if (ct==0) { /* eof */
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eof++;
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return(0);
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}
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if (ct==126) { /* white space */
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if (c=='\n')
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line = line + 1;
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c = xread();
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goto loop;
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}
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if (c=='=') {
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return(subseq('=',80,60));
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}
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if (c=='<') {
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return(subseq('=',63,62));
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}
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if (c=='>') {
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return(subseq('=',65,64));
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}
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if (c=='!') {
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return(subseq('=',34,61));
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}
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if (c=='$') {
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if (subseq('(',0,1))
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return(2);
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if (subseq(')',0,1))
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return(3);
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}
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if (c=='/') {
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if (subseq('*',1,0))
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return(43);
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com:
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c = xread();
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com1:
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if (c==4) {
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eof++;
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error('*/'); /* eof */
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return(0);
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}
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if (c=='\n')
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line++;
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if (c!='*')
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goto com;
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c = xread();
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if (c!='/')
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goto com1;
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c = xread();
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goto loop;
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}
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if (ct==124) { /* number */
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cval = 0;
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if (c=='0')
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b = 8;
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else
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b = 10;
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while(c >= '0' && c <= '9') {
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cval = cval*b + c -'0';
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c = xread();
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}
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peekc = c;
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return(21);
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}
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if (c=='\'') { /* ' */
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getcc();
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return(21);
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}
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if (ct==123) { /* letter */
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sp = symbuf;
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while(ctab[c]==123 | ctab[c]==124) {
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if (sp<symbuf+9) *sp++ = c;
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c = xread();
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}
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*sp = 0;
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peekc = c;
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csym = lookup();
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if (csym[0]==1) {
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cval = csym[1];
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return(19); /* keyword */
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}
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return(20); /* name */
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}
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if (ct==127) { /* unknown */
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error('sy');
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c = xread();
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goto loop;
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}
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return(ctab[c]);
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}
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subseq(c,a,b) {
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extern peekc; // extern xread, peekc;
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if (!peekc)
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peekc = xread();
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if (peekc != c)
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return(a);
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peekc = 0;
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return(b);
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}
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getcc() {
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extern cval;
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auto c;
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cval = 0;
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if ((c = mapch('\'')) < 0) return;
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cval = c;
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if ((c = mapch('\'')) < 0) return;
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cval = cval * 512 + c;
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if ((c = mapch('\'')) >= 0)
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error('cc');
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}
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mapch(c) {
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extern peekc, line;
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auto a;
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if((a=xread())==c)
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return(-1);
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if (a=='\n' | a==0 | a==4) {
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error('cc');
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peekc = a;
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return(-1);
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}
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if (a=='*') {
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a=xread();
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if (a=='0')
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return('\0');
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if (a=='e')
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return(4);
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if (a=='(')
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return('{');
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if (a==')')
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return('}');
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if (a=='t')
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return('\t');
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if (a=='r')
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return('\r');
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if (a=='n')
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return('\n');
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}
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return(a);
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}
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void expr(int lev) {
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int o;
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o = symbol();
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if (o==21) { /* number */
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case21:
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gen('n',5); /* litrl */
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number(cval);
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xwrite('\n');
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goto loop;
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}
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if (o==20) { /* name */
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if (*csym==0) { /* not seen */
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if((peeksym=symbol())==6) { /* ( */
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*csym = 6; /* extrn */
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} else {
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*csym = 2; /* internal */
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csym[1] = ++isn;
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}
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}
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if(*csym==5) /* auto */
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gen('a',csym[1]);
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else {
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xwrite('x ');
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if (*csym==6) { /* extrn */
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xwrite('.');
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name(csym+2);
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} else { /* internal */
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xwrite('l');
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number(csym[1]);
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}
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xwrite('\n');
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}
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goto loop;
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}
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if (o==34) { /* ! */
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expr(1);
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gen('u',4); /* unot */
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goto loop;
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}
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if (o==41) { /* - */
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peeksym = symbol();
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if (peeksym==21) { /* number */
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peeksym = -1;
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cval = -cval;
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goto case21;
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}
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expr(1);
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gen('u',2); /* umin */
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goto loop;
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}
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if (o==47) { /* & */
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expr(1);
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gen('u',1); /* uadr */
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goto loop;
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}
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if (o==42) { /* * */
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expr(1);
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gen('u',3); /* uind */
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goto loop;
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}
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if (o==6) { /* ( */
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peeksym = o;
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pexpr();
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goto loop;
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}
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error('ex');
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loop:
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o = symbol();
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if (lev>=14 & o==80) { /* = */
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expr(14);
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gen('b',1); /* asg */
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goto loop;
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}
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if (lev>=10 & o==48) { /* | ^ */
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expr(9);
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gen('b',2); /* bor */
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goto loop;
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}
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if (lev>=8 & o==47) { /* & */
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expr(7);
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gen('b',3); /* band */
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goto loop;
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}
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if (lev>=7 & o>=60 & o<=61) { /* == != */
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expr(6);
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gen('b',o-56); /* beq bne */
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goto loop;
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}
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if (lev>=6 & o>=62 & o<=65) { /* <= < >= > */
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expr(5);
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gen('b',o-56); /* ble blt bge bgt */
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goto loop;
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}
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if (lev>=4 & o>=40 & o<=41) { /* + - */
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expr(3);
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gen('b',o-28); /* badd bmin */
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goto loop;
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}
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if (lev>=3 & o>=42 & o<=43) { /* * / */
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expr(2);
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gen('b',o-27); /* bmul bdiv */
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goto loop;
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}
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if (lev>=3 & o==44) { /* % */
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expr(2);
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gen('b',14); /* bmod */
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goto loop;
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}
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if (o==4) { /* [ */
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expr(15);
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if (symbol() != 5)
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error('[]');
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gen('b',12); /* badd */
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gen('u',3); /* uind */
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goto loop;
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}
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if (o==6) { /* ( */
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o = symbol();
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if (o==7) /* ) */
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gen('n',1); /* mcall */
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else {
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gen('n',2); /* mark */
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peeksym = o;
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while (o!=7) {
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expr(15);
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o = symbol();
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if (o!=7 && o!=9) { /* ) , */
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error('ex');
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return;
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}
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}
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gen('n',3); /* call */
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}
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goto loop;
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}
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peeksym = o;
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}
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pexpr()
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{
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auto o, t;
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if ((o=symbol())==6) { /* ( */
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expr(15);
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if ((o=symbol())==7) /* ) */
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return;
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}
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error('()');
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}
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declare(kw) {
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// extern csym[], symbol, paraml[], parame[];
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// extern error, cval, peeksym, exit;
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// int t[], n, o;
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int o;
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while((o=symbol())==20) { /* name */
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if (kw==6) { /* extrn */
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*csym = 6;
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o = symbol();
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} else { /* auto/param */
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*csym = 5; /* auto */
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csym[1] = nauto;
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o = symbol();
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if (kw==5 & o==21) { /* auto & number */
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gen('y',nauto); /* aryop */
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nauto = nauto + cval;
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o = symbol();
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}
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nauto++;
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}
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if (o!=9) /* , */
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goto done;
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}
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done:
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if(o==1 & kw!=8 | o==7 & kw==8) /* auto/extrn ; param ')' */
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return;
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syntax:
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error('[]'); /* declaration syntax */
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}
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extdef() {
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// extern eof, cval;
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// extern symbol, block, printf, pname, csym[];
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// extern error;
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auto o, c;
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o = symbol();
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if(o==0 | o==1) /* eof ; */
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return;
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if(o!=20) /* name */
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goto syntax;
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csym[0] = 6; /* extrn */
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xwrite('.');
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name(csym + 2);
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xwrite(': ');
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o=symbol();
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if (o==2 | o==6) { /* $( ( */
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xwrite('.+');
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xwrite('1\n');
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nauto = 2;
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if (o==6) { /* ( */
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declare(8); /* param */
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if ((o=symbol())!=2) /* $( */
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goto syntax;
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}
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while((o=symbol())==19 && cval<10) /* auto extrn */
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declare(cval);
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peeksym = o;
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gen('s',nauto); /* setop */
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stmtlist();
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gen('n',7); /* retrn */
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return;
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}
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if (o==21) { /* number */
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number(cval);
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xwrite('\n');
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return;
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}
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if (o==1) { /* ; */
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xwrite('0\n');
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return;
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}
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if (o==4) { /* [ */
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c = 0;
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if ((o=symbol())==21) { /* number */
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c = cval;
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o = symbol();
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}
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if (o!=5) /* ] */
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goto syntax;
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xwrite('.+');
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xwrite('1\n');
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if ((o=symbol())==1) /* ; */
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goto done;
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while (o==21) { /* number */
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number(cval);
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xwrite('\n');
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c--;
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if ((o=symbol())==1) /* ; */
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goto done;
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if (o!=9) /* , */
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goto syntax;
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else
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o = symbol();
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}
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goto syntax;
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done:
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if (c>0) {
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xwrite('.=');
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xwrite('.+');
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number(c);
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xwrite('\n');
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}
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return;
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}
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|
|
if (o==0) /* eof */
|
|
return;
|
|
|
|
syntax:
|
|
error('xx');
|
|
stmt();
|
|
}
|
|
|
|
stmtlist() {
|
|
int o;
|
|
while (!eof) {
|
|
if ((o = symbol())==3) /* $) */
|
|
return;
|
|
peeksym = o;
|
|
stmt();
|
|
}
|
|
error('$)'); /* missing $) */
|
|
}
|
|
|
|
stmt() {
|
|
// extern symbol, error, blkhed, eof, peeksym;
|
|
// extern blkend, csym[], rcexpr, block[], tree[], regtab[];
|
|
// extern jumpc, jump, label, contlab, brklab, cval;
|
|
// extern swp[], isn, pswitch, peekc, slabel;
|
|
// extern efftab[], declare, deflab, swtab[], swsiz, branch;
|
|
|
|
// int o, o1, o2, np[];
|
|
int o, o1, o2;
|
|
|
|
next:
|
|
o = symbol();
|
|
|
|
if (o==0) /* eof */
|
|
{
|
|
error('fe'); /* Unexpected eof */
|
|
return;
|
|
}
|
|
|
|
if (o==1 || o==3) /* ; $) */
|
|
return;
|
|
|
|
if (o==2) { /* $( */
|
|
stmtlist();
|
|
return;
|
|
}
|
|
|
|
if (o==19) { /* keyword */
|
|
|
|
if (cval==10) { /* goto */
|
|
expr(15);
|
|
gen('n',6); /* goto */
|
|
goto semi;
|
|
}
|
|
|
|
if (cval==11) { /* return */
|
|
if((peeksym=symbol())==6) /* ( */
|
|
pexpr();
|
|
gen('n',7); /* retrn */
|
|
goto semi;
|
|
}
|
|
|
|
if (cval==12) { /* if */
|
|
pexpr();
|
|
isn++;
|
|
o1 = isn;
|
|
jumpc(o1);
|
|
stmt();
|
|
o = symbol();
|
|
if (o==19 & cval==14) { /* else */
|
|
isn++;
|
|
o2 = isn;
|
|
jump(o2);
|
|
label(o1);
|
|
stmt();
|
|
label(o2);
|
|
return;
|
|
}
|
|
peeksym = o;
|
|
label(o1);
|
|
return;
|
|
}
|
|
|
|
if (cval==13) { /* while */
|
|
isn++;
|
|
o1 = isn;
|
|
label(o1);
|
|
pexpr();
|
|
isn++;
|
|
o2 = isn;
|
|
jumpc(o2);
|
|
stmt();
|
|
jump(o1);
|
|
label(o2);
|
|
return;
|
|
}
|
|
|
|
error('sx');
|
|
goto syntax;
|
|
}
|
|
|
|
if (o==20 & peekc==':') { /* name : */
|
|
peekc = 0;
|
|
if (!*csym) {
|
|
*csym = 2; /* param */
|
|
++isn;
|
|
csym[1] = isn;
|
|
} else if (*csym != 2) {
|
|
error('rd');
|
|
goto next;
|
|
}
|
|
label(csym[1]);
|
|
goto next;
|
|
}
|
|
|
|
peeksym = o;
|
|
expr(15);
|
|
gen('s',nauto); /* setop */
|
|
|
|
semi:
|
|
o = symbol();
|
|
if (o==1) /* ; */
|
|
return;
|
|
|
|
syntax:
|
|
error('sz');
|
|
goto next;
|
|
}
|
|
|
|
blkend() {
|
|
while (nisn < isn) {
|
|
++nisn;
|
|
xwrite('l');
|
|
number(nisn);
|
|
xwrite(': ');
|
|
xwrite('ll');
|
|
number(nisn);
|
|
xwrite('\n');
|
|
}
|
|
}
|
|
|
|
gen(o,n) {
|
|
xwrite(o);
|
|
xwrite(' ');
|
|
number(n);
|
|
xwrite('\n');
|
|
}
|
|
|
|
jumpc(n) {
|
|
xwrite('f '); /* ifop */
|
|
xwrite('l');
|
|
number(n);
|
|
xwrite('\n');
|
|
}
|
|
|
|
jump(n) {
|
|
xwrite('t '); /* traop */
|
|
xwrite('ll');
|
|
number(n);
|
|
xwrite('\n');
|
|
}
|
|
|
|
label(n) {
|
|
xwrite('ll');
|
|
number(n);
|
|
xwrite(':\n');
|
|
}
|
|
|
|
printn(n) {
|
|
if (n > 9) {
|
|
printn(n / 10);
|
|
n = n % 10;
|
|
}
|
|
xwrite(n + '0');
|
|
}
|
|
|
|
number(x) {
|
|
if (x < 0) {
|
|
xwrite('-');
|
|
x = -x;
|
|
}
|
|
printn(x);
|
|
}
|
|
|
|
name(int *s) {
|
|
while (*s) {
|
|
xwrite(*s);
|
|
s = s + 1;
|
|
}
|
|
}
|
|
|
|
error(code)
|
|
{
|
|
extern line;
|
|
int f;
|
|
|
|
nerror++;
|
|
xflush();
|
|
f = fout;
|
|
fout = 1;
|
|
xwrite(code);
|
|
xwrite(' ');
|
|
if (code=='rd' | code=='un') {
|
|
name(csym + 2);
|
|
xwrite(' ');
|
|
}
|
|
printn(line);
|
|
xwrite('\n');
|
|
if (nerror==20)
|
|
exit(20);
|
|
fout = f;
|
|
}
|
|
|
|
// runtime:
|
|
|
|
xread() {
|
|
char buf[1];
|
|
if (read(fin, buf, 1) <= 0)
|
|
return 4;
|
|
return buf[0];
|
|
}
|
|
|
|
xwrite(int c) {
|
|
char buf[2];
|
|
if (c & 0xff00) {
|
|
buf[0] = (c >> 8) & 0xff;
|
|
buf[1] = c & 0xff;
|
|
write(fout, buf, 2);
|
|
} else {
|
|
buf[0] = c & 0xff;
|
|
write(fout, buf, 1);
|
|
}
|
|
}
|
|
|
|
xflush() {
|
|
} |