acme/src/encoding.c
marcobaye 496fde6f1a more cleanup
added "outfilestart" keyword to "*="
added "file" keyword to "!convtab"


git-svn-id: https://svn.code.sf.net/p/acme-crossass/code-0/trunk@339 4df02467-bbd4-4a76-a152-e7ce94205b78
2024-02-17 16:52:32 +00:00

90 lines
2.1 KiB
C

// ACME - a crossassembler for producing 6502/65c02/65816/65ce02 code.
// Copyright (C) 1998-2024 Marco Baye
// Have a look at "acme.c" for further info
//
// Character encoding stuff
#include "encoding.h"
// struct definition
struct encoder {
unsigned char (*fn)(unsigned char);
// maybe add table pointer?
};
// variables
static unsigned char outermost_table[256]; // space for encoding table...
const struct encoder *encoder_current; // gets set before each pass
unsigned char *encoding_loaded_table = outermost_table; // ...loaded from file
// encoder functions:
// convert raw to raw (do not convert at all)
static unsigned char encoderfn_raw(unsigned char byte)
{
return byte;
}
// convert raw to petscii
static unsigned char encoderfn_pet(unsigned char byte)
{
if ((byte >= (unsigned char) 'A') && (byte <= (unsigned char) 'Z'))
return byte | 0x80;
if ((byte >= (unsigned char) 'a') && (byte <= (unsigned char) 'z'))
return byte - 32;
return byte;
}
// convert raw to C64 screencode
static unsigned char encoderfn_scr(unsigned char byte)
{
if ((byte >= (unsigned char) 'a') && (byte <= (unsigned char) 'z'))
return byte - 96; // shift uppercase down
if ((byte >= (unsigned char) '[') && (byte <= (unsigned char) '_'))
return byte - 64; // shift [\]^_ down
if (byte == '`')
return 64; // shift ` down
if (byte == '@')
return 0; // shift @ down
return byte;
}
// convert raw to whatever is defined in table
static unsigned char encoderfn_file(unsigned char byte)
{
return encoding_loaded_table[byte];
}
// predefined encoder structs:
const struct encoder encoder_raw = {
encoderfn_raw
};
const struct encoder encoder_pet = {
encoderfn_pet
};
const struct encoder encoder_scr = {
encoderfn_scr
};
const struct encoder encoder_file = {
encoderfn_file
};
// exported functions
// convert character using current encoding (exported for use by alu.c and pseudoopcodes.c)
unsigned char encoding_encode_char(unsigned char byte)
{
return encoder_current->fn(byte);
}
// set "raw" as default encoding
void encoding_passinit(void)
{
encoder_current = &encoder_raw;
}