Commit | Line | Data |
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2b252132 | 1 | /* Kdivd.s 1.2 86/01/03 */ |
b3162c13 | 2 | |
2b252132 SL |
3 | #include "fp.h" |
4 | #include "Kfp.h" | |
5 | #include "SYS.h" | |
b3162c13 | 6 | |
2b252132 | 7 | #define HIDDEN 23 # here we count from 0 not from 1 as in fp.h |
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8 | |
9 | .text | |
2b252132 | 10 | ENTRY(Kdivd, R9|R8|R7|R6|R5|R4|R3|R2) |
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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 |
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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 |