begin_for_step.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"

void begin_for_step( Environment * _environment, char * _index, char * _from, char * _to, char * _step ) {
 
    Variable * index = NULL;
 
    if ( variable_exists( _environment, _index ) ) {
        index = variable_retrieve( _environment, _index );
    } else {
        index = variable_retrieve_or_define( _environment, _index, VT_SWORD, 0 );
    }
 
    outline1("; index = %s", index->realName );
 
    Variable * from = variable_retrieve( _environment, _from );
    Variable * to = variable_retrieve( _environment, _to );
    Variable * step = variable_retrieve( _environment, _step );
 
    Variable * toResident = variable_resident( _environment, to->type, "(resident to)" );
    variable_move_naked( _environment, to->name, toResident->name );
 
    Variable * stepResident = variable_resident( _environment, index->type, "(resident step)" );
    variable_move( _environment, step->name, stepResident->name );
 
    Variable * zero = variable_resident( _environment, VT_WORD, "(zero)" );
    variable_store( _environment, zero->name, 0 );
 
    MAKE_LABEL
 
    Loop * loop = malloc( sizeof( Loop ) );
    memset( loop, 0, sizeof( Loop ) );
    loop->label = strdup( label );
    loop->type = LT_FOR;
    loop->next = _environment->loops;
    loop->index = index;
    loop->index->locked = 1;
    loop->step = stepResident;
    loop->step->locked = 1;
    loop->to = toResident;
    loop->to->locked = 1;
    loop->zero = zero;
    loop->zero->locked = 1;
    _environment->loops = loop;
 
    variable_move( _environment, from->name, index->name );
 
    unsigned char beginFor[MAX_TEMPORARY_STORAGE]; sprintf(beginFor, "%sbf", loop->label );
    unsigned char endFor[MAX_TEMPORARY_STORAGE]; sprintf(endFor, "%sbis", loop->label );
    unsigned char forwardFor[MAX_TEMPORARY_STORAGE]; sprintf(forwardFor, "%sfor", loop->label );
    unsigned char backwardFor[MAX_TEMPORARY_STORAGE]; sprintf(backwardFor, "%sback", loop->label );
    unsigned char continueFor[MAX_TEMPORARY_STORAGE]; sprintf(continueFor, "%scont", loop->label );
 
    cpu_label( _environment, beginFor );
 
    cpu_bvneq( _environment, variable_greater_than( _environment, loop->step->name, zero->name, 0)->realName, forwardFor );
 
    cpu_jump( _environment, backwardFor );
 
    cpu_label( _environment, forwardFor );
 
    cpu_bvneq( _environment, variable_greater_than( _environment, index->name, loop->to->name, 0 )->realName, endFor );
 
    cpu_jump( _environment, continueFor );
 
    cpu_label( _environment, backwardFor );
 
    cpu_bvneq( _environment, variable_less_than( _environment, index->name, loop->to->name, 1 )->realName, endFor );
 
    cpu_label( _environment, continueFor );
 
}