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| Commit | Line | Data |
|---|---|---|
| 50bcbc75 C |
1 | /* file: mlsb.c |
| 2 | ** functions: mlsb(), adback(), dsdiv(), dsadd1(), dsrsh() | |
| 3 | /* Copyright (c) 1982, Regents, University of California */ | |
| 4 | ||
| 5 | struct vl /* very long? */ | |
| 6 | {long high; | |
| 7 | long low; | |
| 8 | }; | |
| 9 | ||
| 10 | long mlsb(utop,ubot,vtop,nqhat) | |
| 11 | long *utop; register long *ubot, *vtop; | |
| 12 | register nqhat; | |
| 13 | { | |
| 14 | register handy, carry; | |
| 15 | struct vl work; | |
| 16 | ||
| 17 | for(carry = 0; utop >= ubot; utop--) { | |
| 18 | ||
| 19 | --vtop; | |
| 20 | asm("addl3 r8,*4(fp),r0"); | |
| 21 | asm("emul r10,(r11),r0,-60(fp)"); | |
| 22 | ||
| 23 | carry = work.high; | |
| 24 | handy = work.low; | |
| 25 | *utop = handy & 0x3fffffff; | |
| 26 | carry <<= 2; | |
| 27 | if(handy & 0x80000000) carry += 2; | |
| 28 | if(handy & 0x40000000) carry += 1; | |
| 29 | } | |
| 30 | return(carry); | |
| 31 | } | |
| 32 | ||
| 33 | long adback(utop,ubot,vtop) | |
| 34 | register long *utop, *ubot, *vtop; | |
| 35 | { | |
| 36 | register handy, carry; | |
| 37 | carry = 0; | |
| 38 | for(; utop >= ubot; utop--) { | |
| 39 | carry += *--vtop; | |
| 40 | carry += *utop; | |
| 41 | *utop = carry & 0x3fffffff; | |
| 42 | /* next junk is faster version of carry >>= 30; */ | |
| 43 | handy = carry; | |
| 44 | carry = 0; | |
| 45 | if(handy & 0x80000000) carry -= 2; | |
| 46 | if(handy & 0x40000000) carry += 1; | |
| 47 | } | |
| 48 | return(carry); | |
| 49 | } | |
| 50 | ||
| 51 | long dsdiv(top,bot,div) | |
| 52 | register long *top, *bot; | |
| 53 | register long div; | |
| 54 | { | |
| 55 | struct vl work; char err; | |
| 56 | register long handy, carry = 0; | |
| 57 | for(carry = 0;bot <= top; bot++) { | |
| 58 | handy = *bot; | |
| 59 | if(carry & 1) handy |= 0x40000000; | |
| 60 | if(carry & 2) handy |= 0x80000000; | |
| 61 | carry >>= 2; | |
| 62 | work.low = handy; | |
| 63 | work.high = carry; | |
| 64 | /* *bot = ediv(&work,div,&err); */ | |
| 65 | /* carry = work.high; */ | |
| 66 | asm("ediv r10,-60(fp),(r11),r8"); | |
| 67 | } | |
| 68 | return(carry); | |
| 69 | } | |
| 70 | ||
| 71 | dsadd1(top,bot) | |
| 72 | long *top, *bot; | |
| 73 | { | |
| 74 | register long *p, work, carry = 0; | |
| 75 | ||
| 76 | /* | |
| 77 | * this assumes canonical inputs | |
| 78 | */ | |
| 79 | for(p = top; p >= bot; p--) { | |
| 80 | work = *p + carry; | |
| 81 | *p = work & 0x3fffffff; | |
| 82 | carry = 0; | |
| 83 | if (work & 0x40000000) carry += 1; | |
| 84 | if (work & 0x80000000) carry -= 2; | |
| 85 | } | |
| 86 | p[1] = work; | |
| 87 | } | |
| 88 | ||
| 89 | long dsrsh(top,bot,ncnt,mask1) | |
| 90 | long *top, *bot; | |
| 91 | long ncnt, mask1; | |
| 92 | { | |
| 93 | register long *p = bot; | |
| 94 | register r = -ncnt, l = 30+ncnt, carry = 0, work, save; | |
| 95 | long mask = -1 ^ mask1; | |
| 96 | ||
| 97 | while(p <= top) { | |
| 98 | save = work = *p; save &= mask; work >>= r; | |
| 99 | carry <<= l; work |= carry; *p++ = work; | |
| 100 | carry = save; | |
| 101 | } | |
| 102 | return(carry); | |
| 103 | } |