Ecrit par - Jean-Louis Vern . jlvern@writeme.com (1999)
- 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
+ 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 program is distributed in the hope that it will be useful,
+
+ 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 General Public License for more details.
-
- You should have received a copy of the GNU General Public License
+ 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!
+ what you give them. Help stamp out software-hoarding!
-------------------------------------------------------------------------*/
-#define MSB_SET(x) ((x >> (8*sizeof(x)-1)) & 1)
+/* Assembler-functions are provided for:
+ mcs51 small
+ mcs51 small stack-auto
+*/
+
+#include <stdbool.h>
+
+#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) && !defined(SDCC_PARMS_IN_BANK1)
+# define _DIVULONG_ASM_SMALL_AUTO
+# else
+# define _DIVULONG_ASM_SMALL
+# endif
+# endif
+# endif
+#endif
-unsigned long _divulong (unsigned long a, unsigned long b)
+#if defined _DIVULONG_ASM_SMALL
+
+static void
+_divlong_dummy (void) _naked
{
- unsigned long reste = 0L;
- unsigned char count = 32;
- short c;
-
- do{
- // reste:a <- 0;
- c = MSB_SET(a);
- a <<= 1;
- reste <<= 1;
- if(c)
- reste |= 1L;
-
- if(reste >= b){
- reste -= b;
- // a <- (result = 1)
- a |= 1L;
- }
- } while(--count);
-
- return a;
+ _asm
+
+ .globl __divulong
+
+ __divulong:
+
+ #define count r2
+
+ #define x0 dpl
+ #define x1 dph
+ #define x2 b
+ #define x3 r3
+
+ #define reste0 r4
+ #define reste1 r5
+ #define reste2 r6
+ #define reste3 r7
+#if !defined(SDCC_PARMS_IN_BANK1)
+
+#if defined(SDCC_NOOVERLAY)
+ .area DSEG (DATA)
+#else
+ .area OSEG (OVR,DATA)
+#endif
+
+ .globl __divulong_PARM_2
+ .globl __divslong_PARM_2
+
+ __divulong_PARM_2:
+ __divslong_PARM_2:
+ .ds 4
+
+ .area CSEG (CODE)
+
+ #define y0 (__divulong_PARM_2)
+ #define y1 (__divulong_PARM_2 + 1)
+ #define y2 (__divulong_PARM_2 + 2)
+ #define y3 (__divulong_PARM_2 + 3)
+#else
+ #define y0 (b1_0)
+ #define y1 (b1_1)
+ #define y2 (b1_2)
+ #define y3 (b1_3)
+#endif // !SDCC_PARMS_IN_BANK1
+ ; parameter x comes in a, b, dph, dpl
+ mov x3,a ; save parameter x3
+
+ mov count,#32
+ clr a
+ mov reste0,a
+ mov reste1,a
+ mov reste2,a
+ mov reste3,a
+
+ ; optimization loop in lp0 until the first bit is shifted into rest
+
+ lp0: mov a,x0 ; x <<= 1
+ add a,x0
+ mov x0,a
+ mov a,x1
+ rlc a
+ mov x1,a
+ mov a,x2
+ rlc a
+ mov x2,a
+ mov a,x3
+ rlc a
+ mov x3,a
+
+ jc in_lp
+ djnz count,lp0
+
+ sjmp exit
+
+ loop: mov a,x0 ; x <<= 1
+ add a,x0
+ mov x0,a
+ mov a,x1
+ rlc a
+ mov x1,a
+ mov a,x2
+ rlc a
+ mov x2,a
+ mov a,x3
+ rlc a
+ mov x3,a
+
+ in_lp: mov a,reste0 ; reste <<= 1
+ rlc a ; feed in carry
+ mov reste0,a
+ mov a,reste1
+ rlc a
+ mov reste1,a
+ mov a,reste2
+ rlc a
+ mov reste2,a
+ mov a,reste3
+ rlc a
+ mov reste3,a
+
+ mov a,reste0 ; reste - y
+ subb a,y0 ; carry is always clear here, because
+ ; reste <<= 1 never overflows
+ mov a,reste1
+ subb a,y1
+ mov a,reste2
+ subb a,y2
+ mov a,reste3
+ subb a,y3
+
+ jc minus ; reste >= y?
+
+ ; -> yes; reste -= y;
+ mov a,reste0
+ subb a,y0 ; carry is always clear here (jc)
+ mov reste0,a
+ mov a,reste1
+ subb a,y1
+ mov reste1,a
+ mov a,reste2
+ subb a,y2
+ mov reste2,a
+ mov a,reste3
+ subb a,y3
+ mov reste3,a
+
+ orl x0,#1
+
+ minus: djnz count,loop ; -> no
+
+ exit: mov a,x3 ; prepare the return value
+ ret
+
+ _endasm ;
}
+
+#elif defined _DIVULONG_ASM_SMALL_AUTO
+
+static void
+_divlong_dummy (void) _naked
+{
+ _asm
+
+ .globl __divulong
+
+ __divulong:
+
+ #define count r2
+
+ #define x0 dpl
+ #define x1 dph
+ #define x2 b
+ #define x3 r3
+
+ #define reste0 r4
+ #define reste1 r5
+ #define reste2 r6
+ #define reste3 r7
+
+ .globl __divlong ; entry point for __divslong
+
+ #define y0 r1
+
+ ; parameter x comes in a, b, dph, dpl
+ mov x3,a ; save parameter x3
+
+ mov a,sp
+ add a,#-2-3 ; 2 bytes return address, 3 bytes param y
+ mov r0,a ; r0 points to y0
+
+ __divlong: ; entry point for __divslong
+
+ mov a,@r0 ; load y0
+ mov r1,a
+ inc r0 ; r0 points to y1
+
+ mov count,#32
+ clr a
+ mov reste0,a
+ mov reste1,a
+ mov reste2,a
+ mov reste3,a
+
+ ; optimization loop in lp0 until the first bit is shifted into rest
+
+ lp0: mov a,x0 ; x <<= 1
+ add a,x0
+ mov x0,a
+ mov a,x1
+ rlc a
+ mov x1,a
+ mov a,x2
+ rlc a
+ mov x2,a
+ mov a,x3
+ rlc a
+ mov x3,a
+
+ jc in_lp
+ djnz count,lp0
+
+ sjmp exit
+
+ loop: mov a,x0 ; x <<= 1
+ add a,x0
+ mov x0,a
+ mov a,x1
+ rlc a
+ mov x1,a
+ mov a,x2
+ rlc a
+ mov x2,a
+ mov a,x3
+ rlc a
+ mov x3,a
+
+ in_lp: mov a,reste0 ; reste <<= 1
+ rlc a ; feed in carry
+ mov reste0,a
+ mov a,reste1
+ rlc a
+ mov reste1,a
+ mov a,reste2
+ rlc a
+ mov reste2,a
+ mov a,reste3
+ rlc a
+ mov reste3,a
+
+ mov a,reste0 ; reste - y
+ subb a,y0 ; carry is always clear here, because
+ ; reste <<= 1 never overflows
+ mov a,reste1
+ subb a,@r0 ; y1
+ mov a,reste2
+ inc r0
+ subb a,@r0 ; y2
+ mov a,reste3
+ inc r0
+ subb a,@r0 ; y3
+ dec r0
+ dec r0
+
+ jc minus ; reste >= y?
+
+ ; -> yes; reste -= y;
+ mov a,reste0
+ subb a,y0 ; carry is always clear here (jc)
+ mov reste0,a
+ mov a,reste1
+ subb a,@r0 ; y1
+ mov reste1,a
+ mov a,reste2
+ inc r0
+ subb a,@r0 ; y2
+ mov reste2,a
+ mov a,reste3
+ inc r0
+ subb a,@r0 ; y3
+ mov reste3,a
+ dec r0
+ dec r0
+
+ orl x0,#1
+
+ minus: djnz count,loop ; -> no
+
+ exit: mov a,x3 ; prepare the return value
+ ret
+
+ _endasm ;
+}
+
+#else // _DIVULONG_ASM
+
+#define MSB_SET(x) ((x >> (8*sizeof(x)-1)) & 1)
+
+unsigned long
+_divulong (unsigned long x, unsigned long y)
+{
+ unsigned long reste = 0L;
+ unsigned char count = 32;
+ BOOL c;
+
+ do
+ {
+ // reste: x <- 0;
+ c = MSB_SET(x);
+ x <<= 1;
+ reste <<= 1;
+ if (c)
+ reste |= 1L;
+
+ if (reste >= y)
+ {
+ reste -= y;
+ // x <- (result = 1)
+ x |= 1L;
+ }
+ }
+ while (--count);
+ return x;
+}
+
+#endif // _DIVULONG_ASM
projects / fw / sdcc / blobdiff