Chip 1997 September/CHIP_CD_1997_09_PL.iso/software/news/wspecem/sources/z80/math16bi.c

C/C++ Source or Header | 1996-05-10 | 5.4 KB | 184 lines

/* Ld8Bits.c: Z80 16 bit arithmetic instructions.
 *
 * Copyright 1996 Rui Fernando Ferreira Ribeiro.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include "env.h"

/*=========================================================================*
 *                            add_hl_ss                                    *
 *=========================================================================*/

#define add_hl_ss(hl,ss,hh,TS) { \
   LOCAL USHORT tmp; \
   \
   T(TS); \
   flags._H = ((((hl) & (USHORT)0xFFF) + ((ss) & (USHORT)0xFFF)) > (USHORT)0xFFF ); \
   flags._N = 0; \
   flags._C = ( (tmp = (USHORT)(hl + (ss))) < hl ); \
   hl = tmp; \
   flags._X = hh & (UCHAR)BIT_5; \
   flags._Y = hh & (UCHAR)BIT_3; \
}


void add_hl_bc() add_hl_ss(HL,BC,H,11);
void add_hl_de() add_hl_ss(HL,DE,H,11);

void add_hl_hl()
{
   T(11);
   flags._H = ((HL & (USHORT)0xFFF) > (USHORT)0x7FF);
   flags._N = 0;
   flags._C = (HL > (USHORT)0x7FFF);
   HL += HL;
   flags._X = H & (UCHAR)BIT_5;
   flags._Y = H & (UCHAR)BIT_3;
}

void add_hl_sp() add_hl_ss(HL,SP,H,11);

void add_ix_bc() add_hl_ss(IX,BC,HX,15);
void add_ix_de() add_hl_ss(IX,DE,HX,15);
void add_ix_ix() add_hl_ss(IX,IX,HX,15);
void add_ix_sp() add_hl_ss(IX,SP,HX,15);

void add_iy_bc() add_hl_ss(IY,BC,HY,15);
void add_iy_de() add_hl_ss(IY,DE,HY,15);
void add_iy_iy() add_hl_ss(IY,IY,HY,15);
void add_iy_sp() add_hl_ss(IY,SP,HY,15);

#undef add_hl_ss

/*=========================================================================*
 *                            adc_hl_ss                                    *
 *=========================================================================*/

#define adc_hl_ss(ss,r) { \
    LOCAL USHORT tmp; \
    \
    T(15); \
    flags._H = (((HL & (USHORT)0xFFF) + ((ss) & (USHORT)0xFFF)) > (USHORT)0xFFF ); \
    flags._N = 0; \
    flags._C = ( (tmp = (USHORT)(HL + (ss) + (USHORT) \
         (flags._C != 0 ))) < (HL+(flags._C != 0 )) ); \
    flags._P = ( ((H & BIT_7) == ((r) & BIT_7)) && ((HL & (USHORT)0x8000) ^ tmp) ); \
    flags._Z = !(HL = tmp); \
    flags._S = (H & BIT_7); \
    flags._X = H & (UCHAR)BIT_5; \
    flags._Y = H & (UCHAR)BIT_3; \
}


/**** ADC overflow: -- = + ou ++ = - */

void adc_hl_bc() adc_hl_ss(BC, B);
void adc_hl_de() adc_hl_ss(DE, D);
void adc_hl_hl() adc_hl_ss(HL, H);
/*
void adc_hl_hl()
{
    LOCAL USHORT tmp;

    T(15);
    flags._H = ((HL & (USHORT)0xFFF) > (USHORT)0x7FF);
    flags._N = 0;
    flags._C = (HL > (USHORT)0x7FFF);
    flags._P = ( (HL & (USHORT)0x8000) ^ tmp);
    flags._Z = !(HL += HL + (flags._C != 0));
    flags._S = (H & BIT_7);
    flags._X = H & (UCHAR)BIT_5;
    flags._Y = H & (UCHAR)BIT_3;
}
*/
void adc_hl_sp() adc_hl_ss(SP, SP >> 8);

#undef adc_hl_ss

/*=========================================================================*
 *                            sbc_hl_ss                                    *
 *=========================================================================*/

#define sbc_hl_ss(ss, r) { \
     LOCAL USHORT tmp; \
     \
     T(15); \
     flags._H = (((ss) & (USHORT)0xFFF) > (HL & (USHORT)0xFFF) ); \
     flags._N = 1; \
     flags._Z = !(tmp = (USHORT)(HL - (ss) - \
                    (USHORT)(flags._C != 0)) ); \
     flags._C = ((ss) > HL)||(tmp>HL); \
     flags._P = ( ((H & BIT_7) != ((r) & BIT_7)) && ((HL & (USHORT)0x8000) ^ tmp) ); \
     flags._S = ((HL = tmp) & (USHORT)0x8000); \
     flags._X = H & (UCHAR)BIT_5; \
     flags._Y = H & (UCHAR)BIT_3; \
}

/**** SBC overflow: -+ = + ou +- = - */

void sbc_hl_bc() sbc_hl_ss(BC, B);
void sbc_hl_de() sbc_hl_ss(DE, D);
void sbc_hl_hl() sbc_hl_ss(HL, H);
/*
void sbc_hl_hl()
{
     LOCAL USHORT tmp;

     T(15);
     flags._N = 1;
     flags._Z = !(flags._S = flags._X = flags._Y =
             HL = (flags._C ? (USHORT)0xffff:(USHORT)0));
     flags._P = flags._C = flags._H = 0;
     HL = tmp;
}
*/
void sbc_hl_sp() sbc_hl_ss(SP, SP >> 8);

#undef sbc_hl_ss

/*=========================================================================*
 *                            inc_ss                                       *
 *=========================================================================*/

#define inc_ss(r,TS) { T(TS); (r)++; }

void inc_bc() inc_ss(BC,6);
void inc_de() inc_ss(DE,6);
void inc_hl() inc_ss(HL,6);
void inc_ix() inc_ss(IX,10);
void inc_iy() inc_ss(IY,10);
void inc_sp() inc_ss(SP,6);

#undef inc_ss

/*=========================================================================*
 *                            dec_ss                                       *
 *=========================================================================*/

#define dec_ss(r,TS) { T(TS); (r)--; }

void dec_bc() dec_ss(BC,6);
void dec_de() dec_ss(DE,6);
void dec_hl() dec_ss(HL,6);
void dec_ix() dec_ss(IX,10);
void dec_iy() dec_ss(IY,10);
void dec_sp() dec_ss(SP,6);

#undef dec_ss

/* EOF: Math16Bi.c */