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| Commit | Line | Data |
|---|---|---|
| 9d1834ba | 1 | /* Kmodf.s 1.3 86/01/05 */ |
| 85e2e771 | 2 | |
| 9d1834ba SL |
3 | #include "../tahoe/SYS.h" |
| 4 | #include "../tahoemath/fp.h" | |
| 85e2e771 SL |
5 | |
| 6 | /* | |
| 2b252132 SL |
7 | * float Kmodf (value, iptr, hfs) |
| 8 | * float value, *iptr; | |
| 9 | * int hfs; | |
| 10 | * | |
| 11 | * Modf returns the fractional part of "value", | |
| 12 | * and stores the integer part indirectly through "iptr". | |
| 13 | */ | |
| 85e2e771 | 14 | .text |
| 2b252132 | 15 | ENTRY(Kmodf, R8|R7|R6|R5|R4|R3|R2) |
| 85e2e771 SL |
16 | /* |
| 17 | * Some initializations: | |
| 18 | */ | |
| 19 | clrl r3 | |
| 20 | movl 4(fp),r0 /* fetch operand to r0. */ | |
| 21 | movl 8(fp),r1 | |
| 22 | movl 12(fp),r6 /* fetch addr of int to r6. */ | |
| 23 | /* | |
| 2b252132 SL |
24 | * get exponent |
| 25 | */ | |
| 85e2e771 SL |
26 | andl3 $EXPMASK,r0,r2 /* r2 will hold the exponent. */ |
| 27 | shrl $EXPSHIFT,r2,r2 | |
| 28 | subl2 $BIAS,r2 /* unbias it. */ | |
| 29 | jleq allfrac /* it's int part is zero. */ | |
| 30 | cmpl r2,$56 | |
| 31 | jgeq allint /* it's fraction part is zero. */ | |
| 32 | /* | |
| 2b252132 SL |
33 | * get fraction |
| 34 | */ | |
| 85e2e771 SL |
35 | movl r0,r4 /* remember the original number. */ |
| 36 | movl r1,r5 | |
| 37 | bbc $31,r0,positive /* if negative remember it. */ | |
| 38 | incl r3 | |
| 39 | positive: | |
| 40 | /* clear the non fraction parts. */ | |
| 41 | andl2 $(0!(EXPMASK | SIGNBIT)),r0 | |
| 42 | /* add the hidden bit. */ | |
| 43 | orl2 $(0!CLEARHID),r0 | |
| 44 | ||
| 45 | cmpl r2,$HID_POS /* see if there are bits to clear only in r0 */ | |
| 46 | jgtr in_r1 /* some bytes in r1 */ | |
| 47 | jeql onlyallr0 /* all r0 must be cleared. */ | |
| 48 | mnegl r2,r7 /* r7 - loop counter. */ | |
| 49 | movl $CLEARHID,r8 /* first bit to clear. */ | |
| 50 | 1: | |
| 51 | andl2 r8,r0 /* clear int. bits from fraction part. */ | |
| 52 | shar $1,r8,r8 | |
| 53 | aoblss $0,r7,1b | |
| 54 | 1: | |
| 55 | andl2 r8,r4 /* clear frac bits for int calculation: */ | |
| 56 | shar $1,r8,r8 | |
| 57 | cmpl $0xffffffff,r8 | |
| 58 | jneq 1b | |
| 59 | clrl r5 | |
| 60 | jmp norm | |
| 61 | ||
| 62 | onlyallr0: | |
| 63 | clrl r0 | |
| 64 | clrl r5 | |
| 65 | jmp norm | |
| 66 | ||
| 67 | in_r1: | |
| 68 | clrl r0 | |
| 69 | subl3 r2,$HID_POS,r7 | |
| 70 | movl $0x7fffffff,r8 | |
| 71 | 1: | |
| 72 | andl2 r8,r1 | |
| 73 | shar $1,r8,r8 | |
| 74 | orl2 $0x80000000,r8 | |
| 75 | aoblss $0,r7,1b | |
| 76 | 1: | |
| 77 | andl2 r8,r5 | |
| 78 | shar $1,r8,r8 | |
| 79 | cmpl $0xffffffff,r8 | |
| 80 | jneq 1b | |
| 81 | norm: | |
| 82 | addl2 $BIAS,r2 /* fnorm expects it biased. */ | |
| 83 | pushl 16(fp) /* hfs */ | |
| 2b252132 | 84 | callf $8,_Kfnorm /* normelize fraction part. */ |
| 85e2e771 SL |
85 | cmpl $0,r0 |
| 86 | jeql 1f | |
| 87 | bbc $0,r3,1f | |
| 88 | orl2 $0x80000000,r0 | |
| 89 | 1: | |
| 90 | movl r4,(r6) /* put int part in place. */ | |
| 91 | movl r5,4(r6) | |
| 92 | ret | |
| 93 | ||
| 94 | allint: | |
| 95 | movl r0,(r6) /* copy the argument to the int addr. */ | |
| 96 | movl r1,4(r6) | |
| 97 | clrl r0 /* clear the fraction part. */ | |
| 98 | clrl r1 | |
| 99 | ret | |
| 100 | ||
| 101 | allfrac: | |
| 102 | /* the fraction is ready in r0. */ | |
| 103 | clrl (r6) /* zero the int part. */ | |
| 104 | clrl 4(r6) | |
| 105 | ret | |
| 106 | ||
| 107 | ret_zero: | |
| 108 | clrl (r6) | |
| 109 | clrl 4(r6) | |
| 110 | clrl r0 | |
| 111 | clrl r1 | |
| 112 | ret |