please dont rip this site

SX Microcontroller Radix Math Method

Binary to BCD unpacked 16 bit to 5 digit

From: John Payson via Scott Dattalo

see http://www.dattalo.com/technical/software/pic/bcd.txt for notes on how this works. Plan on a headache. <GRIN>
[ed: quick guess at speed is that about 200 instructions will be executed and 50 instructions + 7 registers used]

;Takes hex number in NumH:NumL  Returns decimal in ;TenK:Thou:Hund:Tens:Ones
;written by John Payson

;input
;=A3*163 + A2*162 + A1*161 + A0*160
;=A3*4096 + A2*256 + A1*16 + A0
NumH    DS      1       ;A3*16+A2
NumL    DS      1       ;A1*16+A0
;output
;=B4*104 + B3*103 + B2*102 + B1*101 + B0*100
;=B4*10000 + B3*1000 + B2*100 + B1*10 + B0
TenK    DS      1       ;B4
Thou    DS      1       ;B3
Hund    DS      1       ;B2
Tens    DS      1       ;B1
Ones    DS      1       ;B0

        mov     W, <>NumH       ;w  = A2*16+A3
        or      W, #$F0         ;w  = A3-16
        mov     Thou, W         ;B3 = A3-16
        add     Thou, W         ;B3 = 2*(A3-16) = 2A3 - 32
        mov     Hund, W
        mov     W, #$E2
        add     Hund, W         ;B2 = A3-16 - 30 = A3-46
        mov     W, #$32
        add     W, Hund
        mov     Ones, W         ;B0 = A3-46 + 50 = A3+4

        mov     W, NumH         ;w  = A3*16+A2
        and     W, #$0F         ;w  = A2
        add     Hund, W         ;B2 = A3-46 + A2 = A3+A2-46
        add     Hund, W         ;B2 = A3+A2-46  + A2 = A3+2A2-46
        add     Ones, W         ;B0 = A3+4 + A2 = A3+A2+4

        mov     Tens, W
        mov     W, #$E9
        add     Tens, W         ;B1 = A2-23
        mov     W, Tens
        add     Tens, W         ;B1 = 2*(A2-23)
        add     Tens, W         ;B1 = 3*(A2-23) = 3A2-69 (Doh! thanks NG)

        mov     W, <>NumL       ;w  = A0*16+A1
        and     W, #$0F         ;w  = A1
        add     Tens, W         ;B1 = 3A2-69 + A1 = 3A2+A1-69 range -69...-9
        add     Ones, W         ;B0 = A3+A2+4 + A1 = A3+A2+A1+4 and Carry = 0 (thanks NG)

        rl      Tens            ;B1 = 2*(3A2+A1-69) + C = 6A2+2A1-138 and Carry is now 1 as tens register had to be negitive
        rl      Ones            ;B0 = 2*(A3+A2+A1+4) + C = 2A3+2A2+2A1+9 (+9 not +8 due to the carry from prev line, Thanks NG)
        not     Ones            ;B0 = ~(2A3+2A2+2A1+9) = -2A3-2A2-2A1-10 (ones complement plus 1 is twos complement. Thanks SD)
;;Nikolai Golovchenko [golovchenko at MAIL.RU] says: complement [not Ones] can be regarded like:
;;      not     Ones
;;      inc     Ones
;;      dec     Ones
;;First two instructions make up negation. So,
;;Ones  = -Ones - 1
;;      = - 2 * (A3 + A2 + A1) - 9 - 1
;;      = - 2 * (A3 + A2 + A1) - 10
        rl      Ones            ;B0 = 2*(-2A3-2A2-2A1-10) = -4A3-4A2-4A1-20

        mov     W, NumL         ;w  = A1*16+A0
        and     W, #$0F         ;w  = A0
        add     Ones, W         ;B0 = -4A3-4A2-4A1-20 + A0 = A0-4(A3+A2+A1)-20 range -215...-5 Carry=0
        rl      Thou            ;B3 = 2*(2A3 - 32) = 4A3 - 64

        mov     W, #$07         ;w  = 7
        mov     TenK, W         ;B4 = 7

;B0 = A0-4(A3+A2+A1)-20,  -5...-200
;B1 = 6A2+2A1-138,       -18...-138
;B2 = A3+2A2-46,         -1...-46
;B3 = 4A3-64,            -4...-64
;B4 = 7,                 7

; At this point, the original number is
; equal to TenK*10000+Thou*1000+Hund*100+Tens*10+Ones
; if those entities are regarded as two's compliment
; binary.  To be precise, all of them are negative
; except TenK.  Now the number needs to be normal-
; ized, but this can all be done with simple byte
; arithmetic.

        mov     W, #$0A         ;w  = 10
Lb1:                            ;do
        add     Ones, W         ; B0 += 10
        dec     Tens            ; B1 -= 1
        sb      3.0
        ;skip no carry
        jmp     Lb1             ; while B0 < 0
        ;jmp carry
Lb2:                            ;do
        add     Tens, W         ; B1 += 10
        dec     Hund            ; B2 -= 1
        sb      3.0
        jmp     Lb2             ; while B1 < 0
Lb3:                            ;do
        add     Hund, W         ; B2 += 10
        dec     Thou            ; B3 -= 1
        sb      3.0
        jmp     Lb3             ; while B2 < 0
Lb4:                            ;do
        add     Thou, W         ; B3 += 10
        dec     TenK            ; B4 -= 1
        sb      3.0
        jmp     Lb4             ; while B3 < 0

        ret



file: /Techref/scenix/lib/math/radix/b2bu-16b5d_sx.htm, 6KB, , updated: 2004/6/10 14:40, local time: 2024/3/28 08:50,
TOP NEW HELP FIND: 
54.196.27.171:LOG IN

 ©2024 These pages are served without commercial sponsorship. (No popup ads, etc...).Bandwidth abuse increases hosting cost forcing sponsorship or shutdown. This server aggressively defends against automated copying for any reason including offline viewing, duplication, etc... Please respect this requirement and DO NOT RIP THIS SITE. Questions?
Please DO link to this page! Digg it! / MAKE!

<A HREF="http://www.sxlist.com/techref/scenix/lib/math/radix/b2bu-16b5d_sx.htm"> SX Microcontroller Radix Math Method Binary to BCD unpacked 16 bit to 5 digit</A>

After you find an appropriate page, you are invited to your to this massmind site! (posts will be visible only to you before review) Just type a nice message (short messages are blocked as spam) in the box and press the Post button. (HTML welcomed, but not the <A tag: Instead, use the link box to link to another page. A tutorial is available Members can login to post directly, become page editors, and be credited for their posts.


Link? Put it here: 
if you want a response, please enter your email address: 
Attn spammers: All posts are reviewed before being made visible to anyone other than the poster.
Did you find what you needed?

 

Welcome to sxlist.com!


Site supported by
sales, advertizing,
& kind contributors
just like you!

Please don't rip/copy
(here's why

Copies of the site on CD
are available at minimal cost.
 

Welcome to www.sxlist.com!

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  .