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as/lexer.c: move hex/dec parse functions to as/lexer/number.c

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Henrik Hautakoski 2019-03-29 16:01:59 +01:00
parent caed36a936
commit 040caee7f4
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GPG key ID: 839F3A7EAFAEAFAA
4 changed files with 112 additions and 59 deletions
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3
Makefile
View file

@ -29,7 +29,7 @@ m16vm : vm/vm.o vm/cpu.o vm/mm.o vm/instr_decode.o \
vm/syscall.o vm/program.o vm/debug.o lib/libm16.a
$(QUIET_LD)$(LD) $(LDFLAGS) -o $@ $^
m16as : as/as.o as/parser.o as/lexer.o \
m16as : as/as.o as/parser.o as/lexer.o as/lexer/number.o \
as/codegen.o as/symtab.o \
as/ast.o lib/libm16.a
$(QUIET_LD)$(LD) $(LDFLAGS) -o $@ $^
@ -42,6 +42,7 @@ lib/libm16.a : lib/vector.o lib/error.o
clean :
$(RM) as/*.o
$(RM) as/lexer/*.o
$(RM) vm/*.o
$(RM) lib/*.o
$(RM) lib/*.a

62
as/lexer.c
View file

@ -21,6 +21,7 @@
#include <string.h>
#include "asm_error.h"
#include "lexer/grammar.h"
#include "lexer/number.h"
#include "lexer.h"
struct opcode_ent {
@ -67,62 +68,6 @@ static int read_next(struct lexer *lex) {
return c;
}
static int read_hex(FILE *fp, int *out) {
int c, val = 0;
while((c = fgetc(fp)) != EOF) {
char n = 0;
if (lexer_is_num(c)) {
n = c - '0';
}
else if ( (c >= 'a' && c <= 'f')
|| (c >= 'A' && c <= 'F')) {
n = (c % 0x20) + 9;
}
else {
ungetc(c, fp);
break;
}
val = (val * 16) + n;
if (val > 0xFF)
goto overflow;
}
*out = val;
return 0;
overflow:
*out = 0xFF;
return -1;
}
static int read_dec(FILE *fp, int neg, int *out) {
int c, val = 0;
while((c = fgetc(fp)) != EOF) {
if (!lexer_is_num(c)) {
ungetc(c, fp);
break;
}
val = (val * 10) + (c - '0');
// Cool trick here.
// because the range is -128 (0x80) to +127 (0x7F)
// We can do 0x80 - 1 if it is NOT a negative number.
if (val > (0x80 - !neg))
goto overflow;
}
*out = neg ? -1 * val : val;
return 0;
overflow:
*out = neg ? -1 * 0x80 : 0x7F;
return -1;
}
static int read_number(FILE *fp, int *out) {
int neg = 0, c = fgetc(fp);
@ -132,7 +77,7 @@ static int read_number(FILE *fp, int *out) {
c = fgetc(fp);
if (c == 'x') {
// We have a hexadecimal number.
return read_hex(fp, out);
return lexer_read_num_hex(fp, out);
}
ungetc(c, fp);
ungetc('0', fp);
@ -146,7 +91,8 @@ static int read_number(FILE *fp, int *out) {
ungetc(c, fp);
}
return read_dec(fp, neg, out);
// Must be a decimal number.
return lexer_read_num_dec(fp, neg, out);
}
static int parse_number(struct lexer *lex) {

77
as/lexer/number.c Normal file
View file

@ -0,0 +1,77 @@
/* lexer/number.c
*
* Copyright (C) 2018-2019 Henrik Hautakoski <henrik.hautakoski@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301, USA.
*/
#include "grammar.h"
#include "number.h"
int lexer_read_num_hex(FILE *fp, int *out) {
int c, val = 0;
while((c = fgetc(fp)) != EOF) {
char n = 0;
if (lexer_is_num(c)) {
n = c - '0';
}
else if ( (c >= 'a' && c <= 'f')
|| (c >= 'A' && c <= 'F')) {
n = (c % 0x20) + 9;
}
else {
ungetc(c, fp);
break;
}
val = (val * 16) + n;
if (val > 0xFF)
goto overflow;
}
*out = val;
return 0;
overflow:
*out = 0xFF;
return -1;
}
int lexer_read_num_dec(FILE *fp, int neg, int *out) {
int c, val = 0;
while((c = fgetc(fp)) != EOF) {
if (!lexer_is_num(c)) {
ungetc(c, fp);
break;
}
val = (val * 10) + (c - '0');
// Cool trick here.
// because the range is -128 (0x80) to +127 (0x7F)
// We can do 0x80 - 1 if it is NOT a negative number.
if (val > (0x80 - !neg))
goto overflow;
}
*out = neg ? -1 * val : val;
return 0;
overflow:
*out = neg ? -1 * 0x80 : 0x7F;
return -1;
}

29
as/lexer/number.h Normal file
View file

@ -0,0 +1,29 @@
/* lexer/number.h
*
* Copyright (C) 2018-2019 Henrik Hautakoski <henrik.hautakoski@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301, USA.
*/
#ifndef ASM_LEXER_NUMBER_H
#define ASM_LEXER_NUMBER_H
#include <stdio.h>
int lexer_read_num_hex(FILE *fp, int *out);
int lexer_read_num_dec(FILE *fp, int neg, int *out);
#endif /* ASM_LEXER_NUMBER_H */