mirror of
https://github.com/uffejakobsen/acme.git
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2be25080aa
git-svn-id: https://svn.code.sf.net/p/acme-crossass/code-0/trunk@290 4df02467-bbd4-4a76-a152-e7ce94205b78
131 lines
3.1 KiB
C
131 lines
3.1 KiB
C
// ACME - a crossassembler for producing 6502/65c02/65816/65ce02 code.
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// Copyright (C) 1998-2020 Marco Baye
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// Have a look at "acme.c" for further info
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//
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// Character encoding stuff
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#include "encoding.h"
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#include <stdio.h>
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#include <string.h>
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#include "alu.h"
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#include "acme.h"
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#include "dynabuf.h"
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#include "global.h"
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#include "output.h"
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#include "input.h"
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#include "tree.h"
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// struct definition
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struct encoder {
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unsigned char (*fn)(unsigned char);
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// maybe add table pointer?
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};
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// variables
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static unsigned char outermost_table[256]; // space for encoding table...
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const struct encoder *encoder_current; // gets set before each pass
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unsigned char *encoding_loaded_table = outermost_table; // ...loaded from file
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// encoder functions:
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// convert raw to raw (do not convert at all)
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static unsigned char encoderfn_raw(unsigned char byte)
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{
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return byte;
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}
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// convert raw to petscii
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static unsigned char encoderfn_pet(unsigned char byte)
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{
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if ((byte >= (unsigned char) 'A') && (byte <= (unsigned char) 'Z'))
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return byte | 0x80;
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if ((byte >= (unsigned char) 'a') && (byte <= (unsigned char) 'z'))
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return byte - 32;
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return byte;
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}
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// convert raw to C64 screencode
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static unsigned char encoderfn_scr(unsigned char byte)
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{
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if ((byte >= (unsigned char) 'a') && (byte <= (unsigned char) 'z'))
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return byte - 96; // shift uppercase down
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if ((byte >= (unsigned char) '[') && (byte <= (unsigned char) '_'))
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return byte - 64; // shift [\]^_ down
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if (byte == '`')
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return 64; // shift ` down
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if (byte == '@')
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return 0; // shift @ down
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return byte;
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}
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// convert raw to whatever is defined in table
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static unsigned char encoderfn_file(unsigned char byte)
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{
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return encoding_loaded_table[byte];
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}
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// predefined encoder structs:
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const struct encoder encoder_raw = {
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encoderfn_raw
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};
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const struct encoder encoder_pet = {
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encoderfn_pet
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};
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const struct encoder encoder_scr = {
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encoderfn_scr
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};
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const struct encoder encoder_file = {
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encoderfn_file
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};
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// keywords for "!convtab" pseudo opcode
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static struct ronode encoder_tree[] = {
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PREDEF_START,
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//no! PREDEFNODE("file", &encoder_file), "!ct file" is not needed; just use {} after initial loading of table!
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PREDEFNODE("pet", &encoder_pet),
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PREDEFNODE("raw", &encoder_raw),
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PREDEF_END("scr", &encoder_scr),
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// ^^^^ this marks the last element
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};
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// exported functions
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// convert character using current encoding (exported for use by alu.c and pseudoopcodes.c)
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unsigned char encoding_encode_char(unsigned char byte)
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{
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return encoder_current->fn(byte);
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}
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// set "raw" as default encoding
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void encoding_passinit(void)
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{
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encoder_current = &encoder_raw;
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}
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// try to load encoding table from given file
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void encoding_load_from_file(unsigned char target[256], FILE *stream)
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{
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if (fread(target, sizeof(char), 256, stream) != 256)
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Throw_error("Conversion table incomplete.");
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}
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// lookup encoder held in DynaBuf and return its struct pointer (or NULL on failure)
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const struct encoder *encoding_find(void)
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{
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void *node_body;
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// perform lookup
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if (!Tree_easy_scan(encoder_tree, &node_body, GlobalDynaBuf)) {
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Throw_error("Unknown encoding.");
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return NULL;
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}
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return node_body;
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}
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