Mercurial > hg > Members > kono > os9 > sbc09
comparison examples/printval.asm @ 57:2088fd998865
sbc09 directry clean up
| author | Shinji KONO <kono@ie.u-ryukyu.ac.jp> |
|---|---|
| date | Mon, 23 Jul 2018 16:07:12 +0900 |
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| children |
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| 56:4fa2bdb0c457 | 57:2088fd998865 |
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| 1 ;print value as decimal | |
| 2 | |
| 3 org $100 | |
| 4 | |
| 5 ldx #$ff00 | |
| 6 loop: | |
| 7 bsr printdec | |
| 8 ldb #32 | |
| 9 swi2 | |
| 10 leax 1,x | |
| 11 bne loop | |
| 12 sync | |
| 13 | |
| 14 | |
| 15 printdec: | |
| 16 pshs cc,d,x ; save regs | |
| 17 lda #$80 ; init. terminator | |
| 18 nxtdg: | |
| 19 sta ,-s ; push digit term | |
| 20 ldb #16 ; 16 bit counter for rotate | |
| 21 clra ; clear accu and carry | |
| 22 roll: | |
| 23 rola ; divide by 10 using binary | |
| 24 adda #$f6 ; long division, shifting X one | |
| 25 bcs sub ; bit at a time info A and | |
| 26 suba #$f6 ; subtracting 10 which sets | |
| 27 sub: | |
| 28 exg d,x ; C if sub goes, else add 10 | |
| 29 rolb ; back and reset C. Rotating X | |
| 30 rola ; by means of A & B both shifts | |
| 31 exg d,x ; X bits into A and shifts | |
| 32 decb ; result bits into X. Do 17 | |
| 33 bpl roll ; times to get last result bit. | |
| 34 leax ,x ; test X and repeat if | |
| 35 bne nxtdg ; X is not zero | |
| 36 tfr a,b | |
| 37 prog: | |
| 38 orb #$30 ; make into ASCII digit, call | |
| 39 swi2 ; print char | |
| 40 ldb ,s+ ; pull next digit of stack and | |
| 41 bpl prog ; repeat if not terminator | |
| 42 puls cc,d,x,pc ; restore regs and return | |
| 43 | |
| 44 | |
| 45 end | |
| 46 |