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| Commit | Line | Data |
|---|---|---|
| 9d1834ba | 1 | /* Kdivd.s 1.3 86/01/05 */ |
| b3162c13 | 2 | |
| 9d1834ba SL |
3 | #include "../tahoemath/fp.h" |
| 4 | #include "../tahoemath/Kfp.h" | |
| 5 | #include "../tahoe/SYS.h" | |
| b3162c13 | 6 | |
| 2b252132 | 7 | #define HIDDEN 23 # here we count from 0 not from 1 as in fp.h |
| b3162c13 SL |
8 | |
| 9 | .text | |
| 2b252132 | 10 | ENTRY(Kdivd, R9|R8|R7|R6|R5|R4|R3|R2) |
| b3162c13 SL |
11 | clrl r3 # r3 - sign: 0 for positive,1 for negative. |
| 12 | movl 4(fp),r0 | |
| 13 | jgeq 1f | |
| 14 | movl $1,r3 | |
| 15 | 1: movl 12(fp),r2 | |
| 16 | jgeq 2f | |
| 17 | bbc $0,r3,1f # seconed operand is negative. | |
| 18 | clrl r3 # if first was negative, make result positive. | |
| 19 | jmp 2f | |
| 20 | 1: movl $1,r3 # if first was positive, make result negative. | |
| 21 | 2: andl2 $EXPMASK,r0 # compute first 'pure'exponent. | |
| 22 | jeql retz | |
| 23 | shrl $EXPSHIFT,r0,r0 | |
| 24 | subl2 $BIAS,r0 | |
| 25 | andl2 $EXPMASK,r2 # compute seconed 'pure'exponent. | |
| 26 | jeql retz2 | |
| 27 | shrl $EXPSHIFT,r2,r2 | |
| 28 | subl2 $BIAS,r2 | |
| 29 | subl3 r2,r0,r2 # subtruct the exponents. | |
| 30 | addl2 $BIAS,r2 | |
| 31 | jleq underf | |
| 32 | # normalization can make the exp. smaller. | |
| 33 | # | |
| 34 | # We have the sign in r3,the exponent in r2,now is the time to | |
| 35 | # perform the division... | |
| 36 | # | |
| 37 | # fetch dividend. (r4,r5) | |
| 38 | andl3 $(0!(EXPMASK | SIGNBIT)),4(fp),r4 | |
| 39 | orl2 $(0!CLEARHID),r4 | |
| 40 | movl 8(fp),r5 | |
| 41 | ||
| 42 | # fetch divisor : (r6,r7) | |
| 43 | andl3 $(0!(EXPMASK | SIGNBIT)),12(fp),r6 | |
| 44 | orl2 $(0!CLEARHID),r6 | |
| 45 | movl 16(fp),r7 | |
| 46 | ||
| 47 | movl $0,r0 # init r0,r1 to be zeros | |
| 48 | movl $0,r1 | |
| 49 | movl $(0!CLEARHID),r8# r8 first bit to set (if). | |
| 50 | shll $1,r8,r8 # to have one more bit,because we might | |
| 51 | # have to shift left to normelize. | |
| 52 | movl $0,r9 | |
| 53 | ||
| 54 | 2: | |
| 55 | subl2 r7,r5 | |
| 56 | sbwc r6,r4 | |
| 57 | jgeq 1f | |
| 58 | addl2 r7,r5 | |
| 59 | adwc r6,r4 | |
| 60 | shlq $1,r4,r4 | |
| 61 | shrq $1,r8,r8 | |
| 62 | jeql over | |
| 63 | jmp 2b | |
| 64 | 1: | |
| 65 | orl2 r8,r0 | |
| 66 | orl2 r9,r1 | |
| 67 | shlq $1,r4,r4 | |
| 68 | shrq $1,r8,r8 | |
| 69 | jneq 2b | |
| 70 | ||
| 71 | over: | |
| 72 | pushl 20(fp) | |
| 2b252132 | 73 | callf $8,_Kfnorm |
| b3162c13 SL |
74 | sign: |
| 75 | 1: bbc $0,r3,done | |
| 76 | orl2 $SIGNBIT,r0 | |
| 77 | done: ret | |
| 78 | ||
| 79 | retz: | |
| 80 | clrl r0 | |
| 81 | clrl r1 | |
| 82 | ret | |
| 83 | ||
| 84 | retz2: bbc $31,12(fp),z_div | |
| 85 | clrl r0 | |
| 86 | clrl r1 | |
| 87 | ret | |
| 88 | underf: | |
| 89 | orl2 $HFS_UNDF,*20(fp) | |
| 90 | ret | |
| 91 | z_div: | |
| 92 | orl2 $HFS_DIVZ,*20(fp) | |
| 93 | ret |