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Large Pack of OldSkool DOS MOD Trackers
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goattracker_2.68.zip
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src
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asm
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pc.c
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C/C++ Source or Header
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2008-04-01
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2KB
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103 lines
/*
* Copyright (c) 2004 Magnus Lind.
*
* This software is provided 'as-is', without any express or implied warranty.
* In no event will the authors be held liable for any damages arising from
* the use of this software.
*
* Permission is granted to anyone to use this software, alter it and re-
* distribute it freely for any non-commercial, non-profit purpose subject to
* the following restrictions:
*
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software in a
* product, an acknowledgment in the product documentation would be
* appreciated but is not required.
*
* 2. Altered source versions must be plainly marked as such, and must not
* be misrepresented as being the original software.
*
* 3. This notice may not be removed or altered from any distribution.
*
* 4. The names of this software and/or it's copyright holders may not be
* used to endorse or promote products derived from this software without
* specific prior written permission.
*
*/
#include "pc.h"
#include "log.h"
#include <stdlib.h>
static struct expr unset_value[1];
static struct expr *s_pc1;
static int s_pc2;
void pc_dump(int level)
{
}
void pc_set(int pc)
{
s_pc1 = NULL;
s_pc2 = pc;
}
void pc_set_expr(struct expr *pc)
{
s_pc1 = pc;
s_pc2 = 0;
}
struct expr *pc_get()
{
struct expr *old_pc1;
if(s_pc1 == unset_value)
{
LOG(LOG_ERROR, ("PC must be set by a .org(pc) call.\n"));
exit(-1);
}
if(s_pc1 == NULL || s_pc2 != 0)
{
old_pc1 = s_pc1;
s_pc1 = new_expr_number(s_pc2);
s_pc2 = 0;
if(old_pc1 != NULL)
{
s_pc1 = new_expr_op2(PLUS, s_pc1, old_pc1);
}
}
return s_pc1;
}
void pc_add(int offset)
{
if(s_pc1 != unset_value)
{
s_pc2 += offset;
}
}
void pc_add_expr(struct expr *pc)
{
struct expr *old_pc1;
if(s_pc1 != unset_value)
{
old_pc1 = s_pc1;
s_pc1 = pc;
if(old_pc1 != NULL)
{
s_pc1 = new_expr_op2(PLUS, s_pc1, old_pc1);
}
}
}
void pc_unset()
{
pc_set_expr(unset_value);
}