215 lines
3.7 KiB
C
215 lines
3.7 KiB
C
/*-------------------------------------------------------------------------
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_divsint.c :- routine for signed int (16 bit) division. just calls
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routine for unsigned division after sign adjustment
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Written By - Sandeep Dutta . sandeep.dutta@usa.net (1999)
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This library is free software; you can redistribute it and/or modify it
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under the terms of the GNU Library General Public License as published by the
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Free Software Foundation; either version 2, or (at your option) any
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later version.
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This library 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 Library General Public License for more details.
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You should have received a copy of the GNU Library General Public License
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along with this program; if not, write to the Free Software
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Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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In other words, you are welcome to use, share and improve this program.
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You are forbidden to forbid anyone else to use, share and improve
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what you give them. Help stamp out software-hoarding!
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-------------------------------------------------------------------------*/
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#include <sdcc-lib.h>
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#if _SDCC_MANGLES_SUPPORT_FUNS
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unsigned unsigned _divuint (unsigned a, unsigned b);
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#endif
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/* Assembler-functions are provided for:
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mcs51 small
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mcs51 small stack-auto
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*/
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#if !defined(SDCC_USE_XSTACK) && !defined(_SDCC_NO_ASM_LIB_FUNCS)
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# if defined(SDCC_mcs51)
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# if defined(SDCC_MODEL_SMALL)
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# if defined(SDCC_STACK_AUTO)
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# define _DIVSINT_ASM_SMALL_AUTO
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# else
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# define _DIVSINT_ASM_SMALL
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# endif
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# endif
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# endif
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#endif
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#if defined _DIVSINT_ASM_SMALL
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static void
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_divsint_dummy (void) _naked
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{
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_asm
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#define a0 dpl
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#define a1 dph
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.globl __divsint
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// _divsint_PARM_2 shares the same memory with _divuint_PARM_2
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// and is defined in _divuint.c
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#define b0 (__divsint_PARM_2)
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#define b1 (__divsint_PARM_2 + 1)
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__divsint:
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; a1 in dph
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; b1 in (__divsint_PARM_2 + 1)
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clr F0 ; Flag 0 in PSW
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; available to user for general purpose
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mov a,a1
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jnb acc.7,a_not_negative
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setb F0
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clr a
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clr c
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subb a,a0
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mov a0,a
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clr a
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subb a,a1
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mov a1,a
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a_not_negative:
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mov a,b1
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jnb acc.7,b_not_negative
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cpl F0
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clr a
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clr c
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subb a,b0
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mov b0,a
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clr a
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subb a,b1
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mov b1,a
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b_not_negative:
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lcall __divuint
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jnb F0,not_negative
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clr a
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clr c
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subb a,a0
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mov a0,a
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clr a
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subb a,a1
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mov a1,a
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not_negative:
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ret
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_endasm ;
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}
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#elif defined _DIVSINT_ASM_SMALL_AUTO
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static void
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_divsint_dummy (void) _naked
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{
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_asm
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#define a0 dpl
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#define a1 dph
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ar0 = 0 ; BUG register set is not considered
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ar1 = 1
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.globl __divsint
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__divsint:
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clr F0 ; Flag 0 in PSW
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; available to user for general purpose
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mov a,a1
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jnb acc.7,a_not_negative
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setb F0
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clr a
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clr c
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subb a,a0
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mov a0,a
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clr a
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subb a,a1
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mov a1,a
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a_not_negative:
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mov a,sp
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add a,#-2 ; 2 bytes return address
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mov r0,a ; r0 points to b1
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mov a,@r0 ; b1
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jnb acc.7,b_not_negative
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cpl F0
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dec r0
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clr a
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clr c
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subb a,@r0 ; b0
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mov @r0,a
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clr a
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inc r0
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subb a,@r0 ; b1
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mov @r0,a
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b_not_negative:
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mov ar1,@r0 ; b1
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dec r0
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mov ar0,@r0 ; b0
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lcall __divint
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jnb F0,not_negative
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clr a
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clr c
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subb a,a0
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mov a0,a
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clr a
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subb a,a1
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mov a1,a
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not_negative:
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ret
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_endasm ;
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}
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#else // _DIVSINT_ASM_
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int
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_divsint (int a, int b)
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{
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register int r;
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r = _divuint((a < 0 ? -a : a),
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(b < 0 ? -b : b));
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if ( (a < 0) ^ (b < 0))
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return -r;
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else
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return r;
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}
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#endif // _DIVSINT_ASM_
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