/*-------------------------------------------------------------------------
-
_divuint.c :- routine for unsigned int (16 bit) division
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!
-------------------------------------------------------------------------*/
+/* 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)
+# define _DIVUINT_ASM_SMALL_AUTO
+# else
+# define _DIVUINT_ASM_SMALL
+# endif
+# endif
+# endif
+#endif
+
+#if defined _DIVUINT_ASM_SMALL || defined _DIVUINT_ASM_SMALL_AUTO
+
+static void
+_divuint_dummy (void) __naked
+{
+ __asm
+
+ .globl __divuint
+
+__divuint:
+
+ #define count r2
+ #define reste_l r3
+ #define reste_h r4
+ #define xl dpl
+ #define xh dph
+
+#if defined(SDCC_PARMS_IN_BANK1)
+ #define yl (b1_0)
+ #define yh (b1_1)
+#else // SDCC_PARMS_IN_BANK1
+ #if defined(SDCC_STACK_AUTO)
+
+ .globl __divint
+
+ mov a,sp
+ add a,#-2 ; 2 bytes return address
+ mov r0,a ; r0 points to yh
+ mov a,@r0 ; load yh
+ mov r1,a
+ dec r0
+ mov a,@r0 ; load yl
+ mov r0,a
+
+ #define yl r0
+ #define yh r1
+
+__divint: ; entry point for __divsint
+
+
+ #else // SDCC_STACK_AUTO
+
+ #if defined(SDCC_NOOVERLAY)
+ .area DSEG (DATA)
+ #else
+ .area OSEG (OVR,DATA)
+ #endif
+
+ .globl __divuint_PARM_2
+ .globl __divsint_PARM_2
+
+__divuint_PARM_2:
+__divsint_PARM_2:
+ .ds 2
+
+ .area CSEG (CODE)
+
+ #define yl (__divuint_PARM_2)
+ #define yh (__divuint_PARM_2 + 1)
+
+ #endif // SDCC_STACK_AUTO
+#endif // SDCC_PARMS_IN_BANK1
+
+ mov count,#16
+ clr a
+ mov reste_l,a
+ mov reste_h,a
+
+loop:
+ mov a,xl ; x <<= 1
+ add a,acc
+ mov xl,a
+ mov a,xh
+ rlc a
+ mov xh,a
+
+ mov a,reste_l ; reste <<= 1
+ rlc a ; feed in carry
+ mov reste_l,a
+ mov a,reste_h
+ rlc a
+ mov reste_h,a
+
+ mov a,reste_l ; reste - y
+ subb a,yl ; here carry is always clear, because
+ ; reste <<= 1 never overflows
+ mov b,a
+ mov a,reste_h
+ subb a,yh
+
+ jc smaller ; reste >= y?
+
+ mov reste_h,a ; -> yes; reste = reste - y;
+ mov reste_l,b
+ orl xl,#1
+smaller: ; -> no
+ djnz count,loop
+ ret
+
+ __endasm;
+}
+
+#else // defined _DIVUINT_ASM_SMALL || defined _DIVUINT_ASM_SMALL_AUTO
+
#define MSB_SET(x) ((x >> (8*sizeof(x)-1)) & 1)
-unsigned int _divuint (unsigned int a, unsigned int b)
+unsigned int
+_divuint (unsigned int x, unsigned int y)
{
- unsigned int reste = 0 ;
- unsigned short count = 16;
- bit c;
-
- do{
- // reste:a <- 0;
- c = MSB_SET(a);
- a <<= 1;
- reste <<= 1;
- if(c)
- reste |= 1;
-
- if(reste >= b){
- reste -= b;
- // a <- (result = 1)
- a |= 1;
- }
- } while(--count);
-
- return a;
+ unsigned int reste = 0;
+ unsigned char count = 16;
+ BOOL c;
+
+ do
+ {
+ // reste: x <- 0;
+ c = MSB_SET(x);
+ x <<= 1;
+ reste <<= 1;
+ if (c)
+ reste |= 1;
+
+ if (reste >= y)
+ {
+ reste -= y;
+ // x <- (result = 1)
+ x |= 1;
+ }
+ }
+ while (--count);
+ return x;
}
+
+#endif // defined _DIVUINT_ASM_SMALL || defined _DIVUINT_ASM_SMALL_AUTO
projects / fw / sdcc / blobdiff