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DataMuseum.dkPresents historical artifacts from the history of: Commodore CBM-900 |
This is an automatic "excavation" of a thematic subset of
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Length: 2457 (0x999)
Notes: UNIX file
Names: »ddiv.s«
└─⟦f27320a65⟧ Bits:30001972 Commodore 900 hard disk image with partial source code
└─⟦f4b8d8c84⟧ UNIX V7 Filesystem
└─ ⟦this⟧ »libc/crt/ddiv.s«
0x000…020 2f 20 66 6c 6f 61 74 69 6e 67 20 70 6f 69 6e 74 20 70 61 63 6b 61 67 65 20 66 6f 72 20 73 65 67 ┆/ floating point package for seg┆ 0x020…040 6d 65 6e 74 65 64 20 7a 2d 38 30 30 31 0a 2f 20 74 69 6d 6f 74 68 79 20 73 2e 20 6d 75 72 70 68 ┆mented z-8001 / timothy s. murph┆ 0x040…060 79 20 20 31 30 2f 38 34 0a 2f 20 49 45 45 45 20 66 6f 72 6d 61 74 0a 2f 20 64 6f 75 62 6c 65 3a ┆y 10/84 / IEEE format / double:┆ 0x060…080 09 36 33 20 36 32 09 09 35 32 20 35 31 09 09 09 09 30 0a 2f 09 20 20 20 20 20 20 73 69 67 6e 20 ┆ 63 62 52 51 0 / sign ┆ 0x080…0a0 20 62 69 6e 20 65 78 70 20 2b 31 30 32 32 20 20 20 66 72 61 63 74 69 6f 6e 20 28 6d 69 73 73 69 ┆ bin exp +1022 fraction (missi┆ 0x0a0…0c0 6e 67 20 68 69 20 62 69 74 29 0a 2f 20 66 6c 6f 61 74 3a 09 33 31 20 33 30 09 09 32 33 20 32 32 ┆ng hi bit) / float: 31 30 23 22┆ 0x0c0…0e0 09 09 09 09 30 0a 2f 09 20 20 20 20 20 20 73 69 67 6e 20 20 62 69 6e 20 65 78 70 20 2b 31 32 36 ┆ 0 / sign bin exp +126┆ 0x0e0…100 20 20 20 20 66 72 61 63 74 69 6f 6e 20 28 6d 69 73 73 69 6e 67 20 68 69 20 62 69 74 29 0a 2f 0a ┆ fraction (missing hi bit) / ┆ 0x100…120 09 2e 67 6c 6f 62 6c 09 53 53 0a 0a 09 2e 67 6c 6f 62 6c 09 64 72 64 69 76 2c 20 64 6c 64 69 76 ┆ .globl SS .globl drdiv, dldiv┆ 0x120…140 0a 2f 0a 2f 20 64 69 76 69 64 65 20 61 2f 62 20 20 72 65 73 75 6c 74 20 69 6e 20 72 71 34 0a 2f ┆ / / divide a/b result in rq4 /┆ 0x140…160 20 73 65 65 20 6b 6e 75 74 68 20 22 61 72 74 20 6f 66 20 63 6f 6d 70 75 74 65 72 20 70 72 6f 67 ┆ see knuth "art of computer prog┆ 0x160…180 72 61 6d 6d 69 6e 67 22 20 76 6f 6c 2e 32 0a 2f 20 20 66 6f 72 20 65 78 70 6c 61 6e 61 74 69 6f ┆ramming" vol.2 / for explanatio┆ 0x180…1a0 6e 20 6f 66 20 64 6f 75 62 6c 65 20 70 72 65 63 69 73 69 6f 6e 20 64 69 76 69 64 65 0a 2f 20 6c ┆n of double precision divide / l┆ 0x1a0…1c0 69 66 65 20 69 73 20 63 6f 6d 70 6c 69 63 61 74 65 64 20 66 75 72 74 68 65 72 20 62 79 20 74 68 ┆ife is complicated further by th┆ 0x1c0…1e0 65 20 6c 61 63 6b 20 6f 66 20 75 6e 73 69 67 6e 65 64 20 6d 75 6c 74 70 6c 79 20 26 20 64 69 76 ┆e lack of unsigned multply & div┆ 0x1e0…200 69 64 65 0a 2f 0a 2f 20 64 72 64 69 76 28 20 64 61 2c 20 64 62 29 0a 2f 20 64 6c 64 69 76 28 20 ┆ide / / drdiv( da, db) / dldiv( ┆ 0x200…220 64 61 2c 20 26 64 62 29 0a 0a 64 72 64 69 76 3a 0a 09 6c 64 61 09 72 72 32 2c 20 53 53 7c 31 32 ┆da, &db) drdiv: lda rr2, SS|12┆ 0x220…240 28 72 31 35 29 0a 09 6a 72 09 75 6e 2c 20 30 66 0a 64 6c 64 69 76 3a 0a 09 6c 64 6c 09 72 72 32 ┆(r15) jr un, 0f dldiv: ldl rr2┆ 0x240…260 2c 20 53 53 7c 31 32 28 72 31 35 29 0a 30 3a 0a 09 73 75 62 09 72 31 35 2c 20 24 31 36 0a 09 6c ┆, SS|12(r15) 0: sub r15, $16 l┆ 0x260…280 64 6d 09 28 72 72 31 34 29 2c 20 72 36 2c 20 24 38 0a 0a 09 6c 64 09 72 30 2c 20 53 53 7c 32 30 ┆dm (rr14), r6, $8 ld r0, SS|20┆ 0x280…2a0 28 72 31 35 29 0a 09 6c 64 6c 09 72 72 34 2c 20 53 53 7c 32 32 28 72 31 35 29 0a 09 6c 64 09 72 ┆(r15) ldl rr4, SS|22(r15) ld r┆ 0x2a0…2c0 36 2c 20 53 53 7c 32 36 28 72 31 35 29 0a 09 73 75 62 09 72 37 2c 20 72 37 0a 0a 09 6c 64 09 72 ┆6, SS|26(r15) sub r7, r7 ld r┆ 0x2c0…2e0 38 2c 20 28 72 72 32 29 0a 09 6c 64 6c 09 72 72 31 32 2c 20 72 72 32 28 32 29 0a 09 6c 64 09 72 ┆8, (rr2) ldl rr12, rr2(2) ld r┆ 0x2e0…300 31 30 2c 20 72 72 32 28 36 29 0a 09 73 75 62 09 72 31 31 2c 20 72 31 31 0a 0a 09 6c 64 09 72 31 ┆10, rr2(6) sub r11, r11 ld r1┆ 0x300…320 2c 20 24 33 32 37 36 38 0a 09 6c 64 09 72 39 2c 20 72 31 0a 09 61 6e 64 09 72 31 2c 20 72 30 0a ┆, $32768 ld r9, r1 and r1, r0 ┆ 0x320…340 09 78 6f 72 09 72 30 2c 20 72 31 0a 09 63 70 09 72 30 2c 20 24 31 36 0a 09 6a 72 09 6c 74 2c 20 ┆ xor r0, r1 cp r0, $16 jr lt, ┆ 0x340…360 72 65 74 7a 0a 09 61 6e 64 09 72 39 2c 20 72 38 0a 09 78 6f 72 09 72 38 2c 20 72 39 0a 09 78 6f ┆retz and r9, r8 xor r8, r9 xo┆ 0x360…380 72 09 72 31 2c 20 72 39 09 09 2f 20 72 65 73 75 6c 74 20 73 69 67 6e 0a 0a 09 63 70 09 72 38 2c ┆r r1, r9 / result sign cp r8,┆ 0x380…3a0 20 24 31 36 0a 09 6a 72 09 6c 74 2c 20 72 65 74 69 6e 66 0a 09 63 70 09 72 30 2c 20 24 32 30 34 ┆ $16 jr lt, retinf cp r0, $204┆ 0x3a0…3c0 37 2a 31 36 0a 09 6a 72 09 67 65 2c 20 72 65 74 69 6e 66 0a 09 63 70 09 72 38 2c 20 24 32 30 34 ┆7*16 jr ge, retinf cp r8, $204┆ 0x3c0…3e0 37 2a 31 36 0a 09 6a 72 09 67 65 2c 20 72 65 74 7a 0a 09 6c 64 62 09 72 6c 31 2c 20 24 34 09 09 ┆7*16 jr ge, retz ldb rl1, $4 ┆ 0x3e0…400 2f 20 66 6f 72 6d 20 65 78 70 6f 6e 65 6e 74 73 2c 20 66 72 61 63 74 69 6f 6e 73 0a 30 3a 0a 09 ┆/ form exponents, fractions 0: ┆ 0x400…420 73 72 6c 09 72 30 0a 09 72 72 63 09 72 34 0a 09 72 72 63 09 72 35 0a 09 72 72 63 09 72 36 0a 09 ┆srl r0 rrc r4 rrc r5 rrc r6 ┆ 0x420…440 72 72 63 09 72 37 0a 09 73 72 6c 09 72 38 0a 09 72 72 63 09 72 31 32 0a 09 72 72 63 09 72 31 33 ┆rrc r7 srl r8 rrc r12 rrc r13┆ 0x440…460 0a 09 72 72 63 09 72 31 30 0a 09 72 72 63 09 72 31 31 0a 09 64 62 6a 6e 7a 09 72 6c 31 2c 20 30 ┆ rrc r10 rrc r11 dbjnz rl1, 0┆ 0x460…480 62 0a 0a 09 73 65 74 66 6c 67 09 43 0a 09 72 72 63 09 72 34 0a 09 72 72 63 09 72 35 0a 09 72 72 ┆b setflg C rrc r4 rrc r5 rr┆ 0x480…4a0 63 09 72 36 0a 09 72 72 63 09 72 37 0a 0a 09 73 65 74 66 6c 67 09 43 0a 09 72 72 63 09 72 31 32 ┆c r6 rrc r7 setflg C rrc r12┆ 0x4a0…4c0 0a 09 72 72 63 09 72 31 33 0a 09 72 72 63 09 72 31 30 0a 09 72 72 63 09 72 31 31 0a 0a 09 73 75 ┆ rrc r13 rrc r10 rrc r11 su┆ 0x4c0…4e0 62 09 72 30 2c 20 72 38 0a 09 61 64 64 09 72 30 2c 20 24 31 30 32 33 0a 09 6a 72 09 6c 65 2c 20 ┆b r0, r8 add r0, $1023 jr le, ┆ 0x4e0…500 72 65 74 7a 09 2f 20 65 78 70 20 77 69 6c 6c 20 6f 6e 6c 79 20 67 65 74 20 73 6d 61 6c 6c 65 72 ┆retz / exp will only get smaller┆ 0x500…520 09 08 08 08 08 08 0a 09 63 70 09 72 30 2c 20 24 32 30 34 38 0a 09 6a 72 09 67 65 2c 20 72 65 74 ┆ cp r0, $2048 jr ge, ret┆ 0x520…540 69 6e 66 09 2f 20 62 79 20 61 74 20 6d 6f 73 74 20 31 0a 0a 09 73 72 6c 6c 09 72 72 31 32 09 09 ┆inf / by at most 1 srll rr12 ┆ 0x540…560 2f 20 6d 61 6b 65 20 64 69 76 69 73 6f 72 20 70 6f 73 69 74 69 76 65 0a 09 72 72 63 09 72 31 30 ┆/ make divisor positive rrc r10┆ 0x560…580 0a 09 72 72 63 09 72 31 31 0a 0a 09 73 72 6c 6c 09 72 72 34 09 09 2f 20 6d 61 6b 65 20 71 75 6f ┆ rrc r11 srll rr4 / make quo┆ 0x580…5a0 74 69 65 6e 74 20 64 65 66 69 6e 65 64 20 26 20 70 6f 73 69 74 69 76 65 0a 09 72 72 63 09 72 36 ┆tient defined & positive rrc r6┆ 0x5a0…5c0 0a 09 72 72 63 09 72 37 0a 09 73 72 6c 6c 09 72 72 34 0a 09 72 72 63 09 72 36 0a 09 72 72 63 09 ┆ rrc r7 srll rr4 rrc r6 rrc ┆ 0x5c0…5e0 72 37 0a 09 73 72 6c 6c 09 72 72 34 0a 09 72 72 63 09 72 36 0a 09 72 72 63 09 72 37 0a 0a 09 64 ┆r7 srll rr4 rrc r6 rrc r7 d┆ 0x5e0…600 69 76 6c 09 72 71 34 2c 20 72 72 31 32 09 2f 20 72 72 36 20 3d 20 67 6f 6f 64 20 61 70 70 72 6f ┆ivl rq4, rr12 / rr6 = good appro┆ 0x600…620 78 20 74 6f 20 68 69 20 70 61 72 74 20 6f 66 20 71 75 6f 74 69 65 6e 74 0a 09 09 09 09 2f 20 77 ┆x to hi part of quotient / w┆ 0x620…640 65 20 61 64 6a 75 73 74 20 75 73 69 6e 67 20 31 73 74 20 74 65 72 6d 20 6f 66 20 70 6f 77 65 72 ┆e adjust using 1st term of power┆ 0x640…660 20 73 65 72 69 65 73 0a 09 09 09 09 2f 20 61 73 20 69 6e 20 6b 6e 75 74 68 0a 09 73 72 6c 6c 09 ┆ series / as in knuth srll ┆ 0x660…680 72 72 31 30 0a 09 6c 64 09 72 39 2c 20 24 2d 31 0a 09 63 6f 6d 09 72 31 30 0a 09 6e 65 67 09 72 ┆rr10 ld r9, $-1 com r10 neg r┆ 0x680…6a0 31 31 0a 09 73 62 63 09 72 31 30 2c 20 72 39 0a 0a 09 6d 75 6c 74 6c 09 72 71 38 2c 20 72 72 36 ┆11 sbc r10, r9 multl rq8, rr6┆ 0x6a0…6c0 09 2f 20 2d 20 76 6c 20 78 20 77 77 08 6d 20 20 28 20 63 66 20 6b 6e 75 74 68 29 0a 09 73 72 6c ┆ / - vl x ww m ( cf knuth) srl┆ 0x6c0…6e0 6c 09 72 72 34 2c 20 24 31 0a 09 61 64 64 6c 09 72 72 38 2c 20 72 72 34 09 2f 20 2b 20 72 20 28 ┆l rr4, $1 addl rr8, rr4 / + r (┆ 0x6e0…700 20 6e 6f 20 6f 76 66 6c 77 20 73 69 6e 63 65 20 6f 70 70 20 73 69 67 6e 73 29 0a 09 73 72 61 6c ┆ no ovflw since opp signs) sral┆ 0x700…720 09 72 72 38 0a 09 72 72 63 09 72 31 30 0a 09 72 72 63 09 72 31 31 0a 09 64 69 76 6c 09 72 71 38 ┆ rr8 rrc r10 rrc r11 divl rq8┆ 0x720…740 2c 20 72 72 31 32 0a 09 65 78 74 73 6c 09 72 71 38 0a 0a 09 73 6c 6c 6c 09 72 72 31 30 09 09 2f ┆, rr12 extsl rq8 slll rr10 /┆ 0x740…760 20 75 6e 64 6f 20 73 68 69 66 74 73 20 66 6f 72 20 70 6f 73 69 74 69 76 65 6e 65 73 73 0a 09 72 ┆ undo shifts for positiveness r┆ 0x760…780 6c 63 09 72 39 0a 09 73 6c 6c 6c 09 72 72 31 30 0a 09 72 6c 63 09 72 39 0a 0a 09 61 64 64 6c 09 ┆lc r9 slll rr10 rlc r9 addl ┆ 0x780…7a0 72 72 38 2c 20 72 72 36 09 2f 20 66 6f 72 6d 20 71 75 6f 74 69 65 6e 74 20 6f 66 20 66 72 61 63 ┆rr8, rr6 / form quotient of frac┆ 0x7a0…7c0 74 69 6f 6e 73 0a 09 0a 09 73 6c 6c 6c 09 72 72 31 30 0a 09 72 6c 63 09 72 39 0a 09 72 6c 63 09 ┆tions slll rr10 rlc r9 rlc ┆ 0x7c0…7e0 72 38 0a 09 73 6c 6c 6c 09 72 72 31 30 0a 09 72 6c 63 09 72 39 0a 09 72 6c 63 09 72 38 0a 09 6a ┆r8 slll rr10 rlc r9 rlc r8 j┆ 0x7e0…800 72 09 63 2c 20 30 66 0a 09 73 6c 6c 6c 09 72 72 31 30 0a 09 72 6c 63 09 72 39 0a 09 72 6c 63 09 ┆r c, 0f slll rr10 rlc r9 rlc ┆ 0x800…820 72 38 0a 09 64 65 63 09 72 30 0a 09 6a 72 09 6c 65 2c 20 72 65 74 7a 0a 30 3a 09 0a 09 63 70 09 ┆r8 dec r0 jr le, retz 0: cp ┆ 0x820…840 72 30 2c 20 24 32 30 34 37 0a 09 6a 72 09 67 65 2c 20 72 65 74 69 6e 66 0a 0a 09 73 6c 6c 6c 09 ┆r0, $2047 jr ge, retinf slll ┆ 0x840…860 72 72 31 30 0a 09 72 6c 63 09 72 39 0a 09 72 6c 63 09 72 38 0a 09 72 6c 63 09 72 30 0a 09 73 6c ┆rr10 rlc r9 rlc r8 rlc r0 sl┆ 0x860…880 6c 6c 09 72 72 31 30 0a 09 72 6c 63 09 72 39 0a 09 72 6c 63 09 72 38 0a 09 72 6c 63 09 72 30 0a ┆ll rr10 rlc r9 rlc r8 rlc r0 ┆ 0x880…8a0 09 73 6c 6c 6c 09 72 72 31 30 0a 09 72 6c 63 09 72 39 0a 09 72 6c 63 09 72 38 0a 09 72 6c 63 09 ┆ slll rr10 rlc r9 rlc r8 rlc ┆ 0x8a0…8c0 72 30 0a 09 73 6c 6c 6c 09 72 72 31 30 0a 09 72 6c 63 09 72 39 0a 09 72 6c 63 09 72 38 0a 09 72 ┆r0 slll rr10 rlc r9 rlc r8 r┆ 0x8c0…8e0 6c 63 09 72 30 0a 0a 09 6f 72 09 72 30 2c 20 72 31 0a 09 6c 64 09 72 31 2c 20 72 38 0a 09 6c 64 ┆lc r0 or r0, r1 ld r1, r8 ld┆ 0x8e0…900 20 09 72 32 2c 20 72 39 0a 09 6c 64 20 09 72 33 2c 20 72 31 30 0a 39 3a 0a 09 6c 64 6d 09 72 36 ┆ r2, r9 ld r3, r10 9: ldm r6┆ 0x900…920 2c 20 28 72 72 31 34 29 2c 20 24 38 0a 09 69 6e 63 09 72 31 35 2c 20 24 31 36 0a 09 72 65 74 0a ┆, (rr14), $8 inc r15, $16 ret ┆ 0x920…940 72 65 74 7a 3a 0a 09 73 75 62 6c 09 72 72 30 2c 20 72 72 30 0a 09 73 75 62 6c 09 72 72 32 2c 20 ┆retz: subl rr0, rr0 subl rr2, ┆ 0x940…960 72 72 32 0a 09 6a 72 09 75 6e 2c 20 39 62 0a 72 65 74 69 6e 66 3a 0a 09 6c 64 09 72 30 2c 20 24 ┆rr2 jr un, 9b retinf: ld r0, $┆ 0x960…980 32 30 34 37 2a 31 36 0a 09 6f 72 09 72 30 2c 20 72 31 0a 09 73 75 62 09 72 31 2c 20 72 31 0a 09 ┆2047*16 or r0, r1 sub r1, r1 ┆ 0x980…999 73 75 62 6c 09 72 72 32 2c 20 72 72 32 0a 09 6a 72 09 75 6e 2c 20 39 62 0a ┆subl rr2, rr2 jr un, 9b ┆