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124 lines
2.9 KiB
C
124 lines
2.9 KiB
C
/* xa65 - 65xx/65816 cross-assembler and utility suite
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*
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* Copyright (C) 1989-1997 Andre Fachat (a.fachat@physik.tu-chemnitz.de)
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* Maintained by Cameron Kaiser
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*
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* Charset conversion module
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <stdio.h>
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#include <string.h>
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#include "xacharset.h"
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static signed char (*convert_func)(signed char);
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static signed char convert_char_ascii(signed char c) {
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return c;
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}
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/*
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* PETSCII conversion roughly follows the PETSCII to UNICODE
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* mapping at http://www.df.lth.se/~triad/krad/recode/petscii_c64en_lc.txt
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* linked from wikipedia http://en.wikipedia.org/wiki/PETSCII
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*/
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static signed char convert_char_petscii(signed char c) {
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if (c >= 0x41 && c < 0x5b) {
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return c + 0x20;
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}
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if (c >= 0x61 && c < 0x7b) {
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return c - 0x20;
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}
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if (c == 0x7f) {
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return 0x14;
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}
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return c;
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}
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/*
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* Built upon Steve Judd's suggested PETSCII -> screen code algorithm
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* This could probably be written a lot better, but it works.
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* http://www.floodgap.com/retrobits/ckb/display.cgi?572
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*/
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static signed char convert_char_petscreen(signed char c) {
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int i;
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i = (int) convert_char_petscii(c);
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#ifdef SIGH
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fprintf(stderr, "input: %i output: %i\n", c, i);
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#endif
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if (i < 0)
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i += 0x80;
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i ^= 0xe0;
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#ifdef SIGH
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fprintf(stderr, "(1)input: %i output: %i\n", c, i);
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#endif
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i += 0x20;
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i &= 0xff;
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#ifdef SIGH
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fprintf(stderr, "(2)input: %i output: %i\n", c, i);
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#endif
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if (i < 0x80)
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return (signed char) i;
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i += 0x40;
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i &= 0xff;
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#ifdef SIGH
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fprintf(stderr, "(3)input: %i output: %i\n", c, i);
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#endif
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if (i < 0x80)
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return (signed char) i;
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i ^= 0xa0;
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#ifdef SIGH
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fprintf(stderr, "(4)input: %i output: %i\n", c, i);
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#endif
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return (signed char) i;
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}
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static signed char convert_char_high(signed char c) {
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return (c | 0x80);
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}
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typedef struct {
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char *name;
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signed char (*func)(signed char);
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} charset;
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static charset charsets[] = {
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{ "ASCII", convert_char_ascii },
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{ "PETSCII", convert_char_petscii },
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{ "PETSCREEN", convert_char_petscreen },
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{ "HIGH", convert_char_high },
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{ NULL, NULL }
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};
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int set_charset(char *charset_name) {
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int i = 0;
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while (charsets[i].name != NULL) {
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if (strcmp(charsets[i].name, charset_name) == 0) {
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convert_func = charsets[i].func;
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return 0;
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}
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i++;
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}
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return -1;
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}
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signed char convert_char(signed char c) {
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return convert_func(c);
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}
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