1 /*-------------------------------------------------------------------------
2 _divuint.c :- routine for unsigned int (16 bit) division
4 Ecrit par - Jean-Louis Vern . jlvern@writeme.com (1999)
6 This library is free software; you can redistribute it and/or modify it
7 under the terms of the GNU Library General Public License as published by the
8 Free Software Foundation; either version 2, or (at your option) any
11 This library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU Library General Public License for more details.
16 You should have received a copy of the GNU Library General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
20 In other words, you are welcome to use, share and improve this program.
21 You are forbidden to forbid anyone else to use, share and improve
22 what you give them. Help stamp out software-hoarding!
23 -------------------------------------------------------------------------*/
25 /* Assembler-functions are provided for:
27 mcs51 small stack-auto
32 #if !defined(SDCC_USE_XSTACK) && !defined(_SDCC_NO_ASM_LIB_FUNCS)
33 # if defined(SDCC_mcs51)
34 # if defined(SDCC_MODEL_SMALL)
35 # if defined(SDCC_STACK_AUTO)
36 # define _DIVUINT_ASM_SMALL_AUTO
38 # define _DIVUINT_ASM_SMALL
44 #if defined _DIVUINT_ASM_SMALL || defined _DIVUINT_ASM_SMALL_AUTO
47 _divuint_dummy (void) _naked
61 #if defined(SDCC_PARMS_IN_BANK1)
64 #else // SDCC_PARMS_IN_BANK1
65 #if defined(SDCC_STACK_AUTO)
70 add a,#-2 ; 2 bytes return address
71 mov r0,a ; r0 points to yh
81 __divint: ; entry point for __divsint
84 #else // SDCC_STACK_AUTO
86 #if defined(SDCC_NOOVERLAY)
92 .globl __divuint_PARM_2
93 .globl __divsint_PARM_2
101 #define yl (__divuint_PARM_2)
102 #define yh (__divuint_PARM_2 + 1)
104 #endif // SDCC_STACK_AUTO
105 #endif // SDCC_PARMS_IN_BANK1
112 loop: mov a,xl ; x <<= 1
119 mov a,reste_l ; reste <<= 1
120 rlc a ; feed in carry
126 mov a,reste_l ; reste - y
127 subb a,yl ; here carry is always clear, because
128 ; reste <<= 1 never overflows
133 jc smaller ; reste >= y?
135 mov reste_h,a ; -> yes; reste = reste - y;
145 #else // defined _DIVUINT_ASM_SMALL || defined _DIVUINT_ASM_SMALL_AUTO
147 #define MSB_SET(x) ((x >> (8*sizeof(x)-1)) & 1)
150 _divuint (unsigned int x, unsigned int y)
152 unsigned int reste = 0;
153 unsigned char count = 16;
176 #endif // defined _DIVUINT_ASM_SMALL || defined _DIVUINT_ASM_SMALL_AUTO