Commit | Line | Data |
---|---|---|
9d1834ba | 1 | /* Kfnorm.s 1.3 86/01/05 */ |
3c2fd3a8 | 2 | |
9d1834ba SL |
3 | #include "../tahoemath/fp.h" |
4 | #include "../tahoemath/Kfp.h" | |
5 | #include "../tahoe/SYS.h" | |
3c2fd3a8 SL |
6 | |
7 | .text | |
2b252132 | 8 | ENTRY(Kfnorm, R6|R5|R4|R3|R2) |
3c2fd3a8 SL |
9 | # clrl r1 |
10 | movl r0,r4 # copy to temporary. | |
11 | jneq inr0 | |
12 | movl r1,r5 | |
13 | clrl r3 # r3 - pos of m.s.b | |
14 | inr1: ffs r5,r6 | |
15 | incl r6 | |
16 | addl2 r6,r3 | |
17 | shrl r6,r5,r5 | |
18 | jneq inr1 | |
19 | cmpl $0,r3 | |
20 | jeql retzero | |
21 | jmp cmpshift | |
22 | inr0: movl $32,r3 | |
23 | inr00: ffs r4,r6 | |
24 | incl r6 | |
25 | addl2 r6,r3 | |
26 | shrl r6,r4,r4 | |
27 | jneq inr00 | |
28 | ||
29 | cmpshift: | |
30 | # compute the shift (r4). | |
31 | subl3 r3,$HID_R0R1,r4 | |
32 | jlss shiftr # if less then zero we shift right. | |
33 | shlq r4,r0,r0 # else we shift left. | |
34 | subl2 r4,r2 # uodate exponent. | |
35 | jleq underflow # if less then 0 (biased) it is underflow. | |
36 | jmp combine # go to combine exponent and fraction. | |
37 | shiftr: | |
38 | mnegl r4,r4 | |
39 | shrq r4,r0,r0 # shift right. | |
40 | addl2 r4,r2 # update exponent | |
41 | cmpl r2,$256 | |
42 | jgeq overflow # check for overflow. | |
43 | combine: | |
44 | andl2 $CLEARHID,r0 # clear the hidden bit. | |
45 | shal $EXPSHIFT,r2,r2 # shift the exponent to its proper place. | |
46 | orl2 r2,r0 | |
47 | ret | |
48 | ||
49 | underflow: | |
50 | clrl r0 | |
51 | orl2 $HFS_UNDF,*4(fp) | |
52 | ret | |
53 | ||
54 | overflow: | |
55 | orl2 $HFS_OVF,*4(fp) | |
56 | ret | |
57 | retzero: | |
58 | clrl r0 | |
59 | clrl r1 | |
60 | ret |