gbdk-releases/gbdk-lib/libc/_divslong.c
2015-01-10 16:25:09 +01:00

265 lines
4.3 KiB
C

/*-------------------------------------------------------------------------
_divslong.c - routine for division of 32 bit long
Written By - Sandeep Dutta . sandeep.dutta@usa.net (1999)
This library is free software; you can redistribute it and/or modify it
under the terms of the GNU Library General Public License as published by the
Free Software Foundation; either version 2, or (at your option) any
later version.
This library 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 Library General Public License for more details.
You should have received a copy of the GNU Library General Public License
along with this program; if not, write to the Free Software
Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
In other words, you are welcome to use, share and improve this program.
You are forbidden to forbid anyone else to use, share and improve
what you give them. Help stamp out software-hoarding!
-------------------------------------------------------------------------*/
#ifndef GBDK
#include <sdcc-lib.h>
#endif
#if _SDCC_MANGLES_SUPPORT_FUNS || GBDK
unsigned long _divulong (unsigned long a, unsigned long b);
#endif
/* Assembler-functions are provided for:
mcs51 small
mcs51 small stack-auto
*/
#if !defined(SDCC_USE_XSTACK) && !defined(_SDCC_NO_ASM_LIB_FUNCS)
# if defined(SDCC_mcs51)
# if defined(SDCC_MODEL_SMALL)
# if defined(SDCC_STACK_AUTO)
# define _DIVSLONG_ASM_SMALL_AUTO
# else
# define _DIVSLONG_ASM_SMALL
# endif
# endif
# endif
#endif
#if defined _DIVSLONG_ASM_SMALL
static void
_divslong_dummy (void) _naked
{
_asm
#define a0 dpl
#define a1 dph
#define a2 b
#define a3 r3
.globl __divslong
// _divslong_PARM_2 shares the same memory with _divulong_PARM_2
// and is defined in _divulong.c
#define b0 (__divslong_PARM_2)
#define b1 (__divslong_PARM_2 + 1)
#define b2 (__divslong_PARM_2 + 2)
#define b3 (__divslong_PARM_2 + 3)
__divslong:
; a3 in acc
; b3 in (__divslong_PARM_2 + 3)
mov a3,a ; save a3
clr F0 ; Flag 0 in PSW
; available to user for general purpose
jnb acc.7,a_not_negative
setb F0
clr a
clr c
subb a,a0
mov a0,a
clr a
subb a,a1
mov a1,a
clr a
subb a,a2
mov a2,a
clr a
subb a,a3
mov a3,a
a_not_negative:
mov a,b3
jnb acc.7,b_not_negative
cpl F0
clr a
clr c
subb a,b0
mov b0,a
clr a
subb a,b1
mov b1,a
clr a
subb a,b2
mov b2,a
clr a
subb a,b3
mov b3,a
b_not_negative:
mov a,a3 ; restore a3 in acc
lcall __divulong
jnb F0,not_negative
mov a3,a ; save a3
clr a
clr c
subb a,a0
mov a0,a
clr a
subb a,a1
mov a1,a
clr a
subb a,a2
mov a2,a
clr a
subb a,a3
mov a3,a
not_negative:
ret
_endasm ;
}
#elif defined _DIVSLONG_ASM_SMALL_AUTO
static void
_divslong_dummy (void) _naked
{
_asm
#define a0 dpl
#define a1 dph
#define a2 b
#define a3 r3
.globl __divslong
__divslong:
; a3 in acc
mov a3,a ; save a3
clr F0 ; Flag 0 in PSW
; available to user for general purpose
jnb acc.7,a_not_negative
setb F0
clr a
clr c
subb a,a0
mov a0,a
clr a
subb a,a1
mov a1,a
clr a
subb a,a2
mov a2,a
clr a
subb a,a3
mov a3,a
a_not_negative:
mov a,sp
add a,#-2 ; 2 bytes return address
mov r0,a ; r0 points to b3
mov a,@r0 ; b3
jnb acc.7,b_not_negative
cpl F0
dec r0
dec r0
dec r0
clr a
clr c
subb a,@r0 ; b0
mov @r0,a
clr a
inc r0
subb a,@r0 ; b1
mov @r0,a
clr a
inc r0
subb a,@r0 ; b2
mov @r0,a
clr a
inc r0
subb a,@r0 ; b3
mov @r0,a
b_not_negative:
dec r0
dec r0
dec r0 ; r0 points to b0
lcall __divlong
jnb F0,not_negative
mov a3,a ; save a3
clr a
clr c
subb a,a0
mov a0,a
clr a
subb a,a1
mov a1,a
clr a
subb a,a2
mov a2,a
clr a
subb a,a3
mov a3,a
not_negative:
ret
_endasm ;
}
#else // _DIVSLONG_ASM
long
_divslong (long a, long b)
{
long r;
r = _divulong((a < 0 ? -a : a),
(b < 0 ? -b : b));
if ( (a < 0) ^ (b < 0))
return -r;
else
return r;
}
#endif // _DIVSLONG_ASM