charset_at.c

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/*****************************************************************************
 * ugBASIC - an isomorphic BASIC language compiler for retrocomputers        *
 *****************************************************************************
 * Copyright 2021-2026 Marco Spedaletti (asimov@mclink.it)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *----------------------------------------------------------------------------
 * Concesso in licenza secondo i termini della Licenza Apache, versione 2.0
 * (la "Licenza"); è proibito usare questo file se non in conformità alla
 * Licenza. Una copia della Licenza è disponibile all'indirizzo:
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Se non richiesto dalla legislazione vigente o concordato per iscritto,
 * il software distribuito nei termini della Licenza è distribuito
 * "COSÌ COM'È", SENZA GARANZIE O CONDIZIONI DI ALCUN TIPO, esplicite o
 * implicite. Consultare la Licenza per il testo specifico che regola le
 * autorizzazioni e le limitazioni previste dalla medesima.
 ****************************************************************************/
 
/****************************************************************************
 * INCLUDE SECTION 
 ****************************************************************************/
 
#include "../../../ugbc.h"
 
/****************************************************************************
 * CODE SECTION
 ****************************************************************************/
 
#if defined(__c64__) || defined(__c64reu__) || defined(__c128__)

/* <usermanual>
@keyword CHARSET AT
@target c64
</usermanual> */
void charset_at( Environment * _environment, int _address ) {
 
    outline0("LDA $d018" );
    outline0("AND #$f1" );
    outline1("ORA #$%2.2x", ( ( _address >> 11 ) & 0x07 ) << 1 );
    outline0("STA $d018" );
 
}

void charset_at_var( Environment * _environment, char * _address ) {
 
    outline1("LDA %s", address_displacement( _environment, _address, "1" ));
    outline0("LSR" );
    outline0("LSR" );
    outline0("LSR" );
    outline0("AND #$07" );
    outline0("ASL" );
    outline0("STA MATHPTR0" );
    outline0("LDA $d018" );
    outline0("AND #$f1" );
    outline0("ORA MATHPTR0" );
    outline0("STA $d018" );
 
}
 
void charset_uppercase( Environment * _environment ) {
    charset_at( _environment, 0x1800 );
}
 
void charset_lowercase( Environment * _environment ) {
    charset_at( _environment, 0x3800 );
}
 
#endif