334 lines
7.2 KiB
C
Executable File
334 lines
7.2 KiB
C
Executable File
/* load.c: This code "loads" code into the code segments. */
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/* This file is part of bc written for MINIX.
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Copyright (C) 1991, 1992 Free Software Foundation, Inc.
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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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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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You should have received a copy of the GNU General Public License
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along with this program; see the file COPYING. If not, write to
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the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
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You may contact the author by:
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e-mail: phil@cs.wwu.edu
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us-mail: Philip A. Nelson
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Computer Science Department, 9062
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Western Washington University
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Bellingham, WA 98226-9062
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*************************************************************************/
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#include "bcdefs.h"
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#include "global.h"
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#include "proto.h"
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/* Load variables. */
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program_counter load_adr;
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char load_str;
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char load_const;
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/* Initialize the load sequence. */
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void
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init_load ()
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{
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clear_func(0);
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load_adr.pc_func = 0;
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load_adr.pc_addr = 0;
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load_str = FALSE;
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load_const = FALSE;
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}
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/* addbyte adds one BYTE to the current code segment. */
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void
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addbyte (byte)
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char byte;
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{
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int seg, offset, func;
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/* If there was an error, don't continue. */
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if (had_error) return;
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/* Calculate the segment and offset. */
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seg = load_adr.pc_addr >> BC_SEG_LOG;
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offset = load_adr.pc_addr++ % BC_SEG_SIZE;
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func = load_adr.pc_func;
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if (seg >= BC_MAX_SEGS)
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{
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yyerror ("Function too big.");
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return;
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}
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if (functions[func].f_body[seg] == NULL)
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functions[func].f_body[seg] = (char *) bc_malloc (BC_SEG_SIZE);
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/* Store the byte. */
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functions[func].f_body[seg][offset] = byte;
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functions[func].f_code_size++;
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}
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/* Define a label LAB to be the current program counter. */
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void
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def_label (lab)
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long lab;
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{
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bc_label_group *temp;
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int group, offset, func;
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/* Get things ready. */
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group = lab >> BC_LABEL_LOG;
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offset = lab % BC_LABEL_GROUP;
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func = load_adr.pc_func;
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/* Make sure there is at least one label group. */
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if (functions[func].f_label == NULL)
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{
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functions[func].f_label =
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(bc_label_group *) bc_malloc (sizeof(bc_label_group));
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functions[func].f_label->l_next = NULL;
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}
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/* Add the label group. */
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temp = functions[func].f_label;
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while (group > 0)
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{
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if (temp->l_next == NULL)
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{
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temp->l_next = (bc_label_group *) bc_malloc (sizeof(bc_label_group));
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temp->l_next->l_next = NULL;
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}
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temp = temp->l_next;
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group --;
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}
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/* Define it! */
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temp->l_adrs [offset] = load_adr.pc_addr;
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}
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/* Several instructions have integers in the code. They
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are all known to be legal longs. So, no error code
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is added. STR is the pointer to the load string and
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must be moved to the last non-digit character. */
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long
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long_val (str)
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char **str;
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{ int val = 0;
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char neg = FALSE;
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if (**str == '-')
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{
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neg = TRUE;
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(*str)++;
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}
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while (isdigit(**str))
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val = val*10 + *(*str)++ - '0';
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if (neg)
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return -val;
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else
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return val;
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}
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/* load_code loads the CODE into the machine. */
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void
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load_code (code)
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char *code;
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{
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char *str;
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long ap_name; /* auto or parameter name. */
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long label_no;
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long vaf_name; /* variable, array or function number. */
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long func;
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program_counter save_adr;
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/* Initialize. */
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str = code;
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/* Scan the code. */
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while (*str != 0)
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{
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/* If there was an error, don't continue. */
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if (had_error) return;
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if (load_str)
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{
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if (*str == '"') load_str = FALSE;
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addbyte (*str++);
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}
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else
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if (load_const)
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{
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if (*str == '\n')
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str++;
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else
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{
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if (*str == ':')
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{
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load_const = FALSE;
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addbyte (*str++);
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}
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else
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if (*str == '.')
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addbyte (*str++);
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else
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if (*str >= 'A')
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addbyte (*str++ + 10 - 'A');
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else
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addbyte (*str++ - '0');
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}
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}
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else
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{
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switch (*str)
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{
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case '"': /* Starts a string. */
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load_str = TRUE;
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break;
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case 'N': /* A label */
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str++;
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label_no = long_val (&str);
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def_label (label_no);
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break;
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case 'B': /* Branch to label. */
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case 'J': /* Jump to label. */
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case 'Z': /* Branch Zero to label. */
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addbyte(*str++);
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label_no = long_val (&str);
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if (label_no > 65535L)
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{ /* Better message? */
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fprintf (stderr,"Program too big.\n");
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exit(1);
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}
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addbyte ( (char) label_no & 0xFF);
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addbyte ( (char) label_no >> 8);
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break;
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case 'F': /* A function, get the name and initialize it. */
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str++;
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func = long_val (&str);
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clear_func (func);
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#if DEBUG > 2
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printf ("Loading function number %d\n", func);
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#endif
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/* get the parameters */
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while (*str++ != '.')
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{
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if (*str == '.')
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{
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str++;
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break;
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}
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ap_name = long_val (&str);
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#if DEBUG > 2
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printf ("parameter number %d\n", ap_name);
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#endif
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functions[(int)func].f_params =
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nextarg (functions[(int)func].f_params, ap_name);
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}
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/* get the auto vars */
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while (*str != '[')
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{
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if (*str == ',') str++;
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ap_name = long_val (&str);
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#if DEBUG > 2
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printf ("auto number %d\n", ap_name);
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#endif
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functions[(int)func].f_autos =
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nextarg (functions[(int)func].f_autos, ap_name);
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}
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save_adr = load_adr;
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load_adr.pc_func = func;
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load_adr.pc_addr = 0;
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break;
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case ']': /* A function end */
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functions[load_adr.pc_func].f_defined = TRUE;
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load_adr = save_adr;
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break;
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case 'C': /* Call a function. */
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addbyte (*str++);
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func = long_val (&str);
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if (func < 128)
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addbyte ( (char) func);
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else
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{
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addbyte ((func >> 8) & 0xff | 0x80);
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addbyte (func & 0xff);
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}
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if (*str == ',') str++;
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while (*str != ':')
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addbyte (*str++);
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addbyte (':');
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break;
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case 'c': /* Call a special function. */
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addbyte (*str++);
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addbyte (*str);
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break;
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case 'K': /* A constant.... may have an "F" in it. */
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addbyte (*str);
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load_const = TRUE;
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break;
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case 'd': /* Decrement. */
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case 'i': /* Increment. */
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case 'l': /* Load. */
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case 's': /* Store. */
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case 'A': /* Array Increment */
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case 'M': /* Array Decrement */
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case 'L': /* Array Load */
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case 'S': /* Array Store */
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addbyte (*str++);
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vaf_name = long_val (&str);
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if (vaf_name < 128)
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addbyte (vaf_name);
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else
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{
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addbyte ((vaf_name >> 8) & 0xff | 0x80);
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addbyte (vaf_name & 0xff);
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}
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break;
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case '@': /* A command! */
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switch (*(++str))
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{
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case 'i':
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init_load ();
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break;
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case 'r':
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execute ();
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break;
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}
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break;
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case '\n': /* Ignore the newlines */
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break;
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default: /* Anything else */
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addbyte (*str);
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}
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str++;
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}
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}
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}
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