1/* Kfnorm.s 1.3 86/01/05 */ 2 3#include "../tahoemath/fp.h" 4#include "../tahoemath/Kfp.h" 5#include "../tahoe/SYS.h" 6 7 .text 8ENTRY(Kfnorm, R6|R5|R4|R3|R2) 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 14inr1: 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 22inr0: movl $32,r3 23inr00: ffs r4,r6 24 incl r6 25 addl2 r6,r3 26 shrl r6,r4,r4 27 jneq inr00 28 29cmpshift: 30 # compute the shift (r4). 31 subl3 r3,$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. 37shiftr: 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. 43combine: 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 49underflow: 50 clrl r0 51 orl2 $HFS_UNDF,*4(fp) 52 ret 53 54overflow: 55 orl2 $HFS_OVF,*4(fp) 56 ret 57retzero: 58 clrl r0 59 clrl r1 60 ret 61