binstr.sa revision 1.2
1 * MOTOROLA MICROPROCESSOR & MEMORY TECHNOLOGY GROUP 2 * M68000 Hi-Performance Microprocessor Division 3 * M68040 Software Package 4 * 5 * M68040 Software Package Copyright (c) 1993, 1994 Motorola Inc. 6 * All rights reserved. 7 * 8 * THE SOFTWARE is provided on an "AS IS" basis and without warranty. 9 * To the maximum extent permitted by applicable law, 10 * MOTOROLA DISCLAIMS ALL WARRANTIES WHETHER EXPRESS OR IMPLIED, 11 * INCLUDING IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A 12 * PARTICULAR PURPOSE and any warranty against infringement with 13 * regard to the SOFTWARE (INCLUDING ANY MODIFIED VERSIONS THEREOF) 14 * and any accompanying written materials. 15 * 16 * To the maximum extent permitted by applicable law, 17 * IN NO EVENT SHALL MOTOROLA BE LIABLE FOR ANY DAMAGES WHATSOEVER 18 * (INCLUDING WITHOUT LIMITATION, DAMAGES FOR LOSS OF BUSINESS 19 * PROFITS, BUSINESS INTERRUPTION, LOSS OF BUSINESS INFORMATION, OR 20 * OTHER PECUNIARY LOSS) ARISING OF THE USE OR INABILITY TO USE THE 21 * SOFTWARE. Motorola assumes no responsibility for the maintenance 22 * and support of the SOFTWARE. 23 * 24 * You are hereby granted a copyright license to use, modify, and 25 * distribute the SOFTWARE so long as this entire notice is retained 26 * without alteration in any modified and/or redistributed versions, 27 * and that such modified versions are clearly identified as such. 28 * No licenses are granted by implication, estoppel or otherwise 29 * under any patents or trademarks of Motorola, Inc. 30 31 * 32 * binstr.sa 3.3 12/19/90 33 * 34 * 35 * Description: Converts a 64-bit binary integer to bcd. 36 * 37 * Input: 64-bit binary integer in d2:d3, desired length (LEN) in 38 * d0, and a pointer to start in memory for bcd characters 39 * in d0. (This pointer must point to byte 4 of the first 40 * lword of the packed decimal memory string.) 41 * 42 * Output: LEN bcd digits representing the 64-bit integer. 43 * 44 * Algorithm: 45 * The 64-bit binary is assumed to have a decimal point before 46 * bit 63. The fraction is multiplied by 10 using a mul by 2 47 * shift and a mul by 8 shift. The bits shifted out of the 48 * msb form a decimal digit. This process is iterated until 49 * LEN digits are formed. 50 * 51 * A1. Init d7 to 1. D7 is the byte digit counter, and if 1, the 52 * digit formed will be assumed the least significant. This is 53 * to force the first byte formed to have a 0 in the upper 4 bits. 54 * 55 * A2. Beginning of the loop: 56 * Copy the fraction in d2:d3 to d4:d5. 57 * 58 * A3. Multiply the fraction in d2:d3 by 8 using bit-field 59 * extracts and shifts. The three msbs from d2 will go into 60 * d1. 61 * 62 * A4. Multiply the fraction in d4:d5 by 2 using shifts. The msb 63 * will be collected by the carry. 64 * 65 * A5. Add using the carry the 64-bit quantities in d2:d3 and d4:d5 66 * into d2:d3. D1 will contain the bcd digit formed. 67 * 68 * A6. Test d7. If zero, the digit formed is the ms digit. If non- 69 * zero, it is the ls digit. Put the digit in its place in the 70 * upper word of d0. If it is the ls digit, write the word 71 * from d0 to memory. 72 * 73 * A7. Decrement d6 (LEN counter) and repeat the loop until zero. 74 * 75 * Implementation Notes: 76 * 77 * The registers are used as follows: 78 * 79 * d0: LEN counter 80 * d1: temp used to form the digit 81 * d2: upper 32-bits of fraction for mul by 8 82 * d3: lower 32-bits of fraction for mul by 8 83 * d4: upper 32-bits of fraction for mul by 2 84 * d5: lower 32-bits of fraction for mul by 2 85 * d6: temp for bit-field extracts 86 * d7: byte digit formation word;digit count {0,1} 87 * a0: pointer into memory for packed bcd string formation 88 * 89 90 BINSTR IDNT 2,1 Motorola 040 Floating Point Software Package 91 92 section 8 93 94 include fpsp.h 95 96 xdef binstr 97 binstr: 98 movem.l d0-d7,-(a7) 99 * 100 * A1: Init d7 101 * 102 moveq.l #1,d7 ;init d7 for second digit 103 subq.l #1,d0 ;for dbf d0 would have LEN+1 passes 104 * 105 * A2. Copy d2:d3 to d4:d5. Start loop. 106 * 107 loop: 108 move.l d2,d4 ;copy the fraction before muls 109 move.l d3,d5 ;to d4:d5 110 * 111 * A3. Multiply d2:d3 by 8; extract msbs into d1. 112 * 113 bfextu d2{0:3},d1 ;copy 3 msbs of d2 into d1 114 asl.l #3,d2 ;shift d2 left by 3 places 115 bfextu d3{0:3},d6 ;copy 3 msbs of d3 into d6 116 asl.l #3,d3 ;shift d3 left by 3 places 117 or.l d6,d2 ;or in msbs from d3 into d2 118 * 119 * A4. Multiply d4:d5 by 2; add carry out to d1. 120 * 121 add.l d5,d5 ;mul d5 by 2 122 addx.l d4,d4 ;mul d4 by 2 123 swap d6 ;put 0 in d6 lower word 124 addx.w d6,d1 ;add in extend from mul by 2 125 * 126 * A5. Add mul by 8 to mul by 2. D1 contains the digit formed. 127 * 128 add.l d5,d3 ;add lower 32 bits 129 nop ;ERRATA FIX #13 (Rev. 1.2 6/6/90) 130 addx.l d4,d2 ;add with extend upper 32 bits 131 nop ;ERRATA FIX #13 (Rev. 1.2 6/6/90) 132 addx.w d6,d1 ;add in extend from add to d1 133 swap d6 ;with d6 = 0; put 0 in upper word 134 * 135 * A6. Test d7 and branch. 136 * 137 tst.w d7 ;if zero, store digit & to loop 138 beq.b first_d ;if non-zero, form byte & write 139 sec_d: 140 swap d7 ;bring first digit to word d7b 141 asl.w #4,d7 ;first digit in upper 4 bits d7b 142 add.w d1,d7 ;add in ls digit to d7b 143 move.b d7,(a0)+ ;store d7b byte in memory 144 swap d7 ;put LEN counter in word d7a 145 clr.w d7 ;set d7a to signal no digits done 146 dbf.w d0,loop ;do loop some more! 147 bra.b end_bstr ;finished, so exit 148 first_d: 149 swap d7 ;put digit word in d7b 150 move.w d1,d7 ;put new digit in d7b 151 swap d7 ;put LEN counter in word d7a 152 addq.w #1,d7 ;set d7a to signal first digit done 153 dbf.w d0,loop ;do loop some more! 154 swap d7 ;put last digit in string 155 lsl.w #4,d7 ;move it to upper 4 bits 156 move.b d7,(a0)+ ;store it in memory string 157 * 158 * Clean up and return with result in fp0. 159 * 160 end_bstr: 161 movem.l (a7)+,d0-d7 162 rts 163 end 164
Indexes created Mon Sep 29 21:09:56 GMT 2025