projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| a6730a00 | 1 | /* Kfnorm.s 1.4 90/12/04 */ |
| 3c2fd3a8 | 2 | |
| a6730a00 KB |
3 | #include "../math/fp.h" |
| 4 | #include "../math/Kfp.h" | |
| 9d1834ba | 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 |