1! Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007 2! Imagination Technologies Ltd 3! 4! Integer divide routines. 5! 6 7 .text 8 .global ___udivsi3 9 .type ___udivsi3,function 10 .align 2 11___udivsi3: 12!! 13!! Since core is signed divide case, just set control variable 14!! 15 MOV D1Re0,D0Ar2 ! Au already in A1Ar1, Bu -> D1Re0 16 MOV D0Re0,#0 ! Result is 0 17 MOV D0Ar4,#0 ! Return positive result 18 B $LIDMCUStart 19 .size ___udivsi3,.-___udivsi3 20 21!! 22!! 32-bit division signed i/p - passed signed 32-bit numbers 23!! 24 .global ___divsi3 25 .type ___divsi3,function 26 .align 2 27___divsi3: 28!! 29!! A already in D1Ar1, B already in D0Ar2 -> make B abs(B) 30!! 31 MOV D1Re0,D0Ar2 ! A already in A1Ar1, B -> D1Re0 32 MOV D0Re0,#0 ! Result is 0 33 XOR D0Ar4,D1Ar1,D1Re0 ! D0Ar4 -ive if result is -ive 34 ABS D1Ar1,D1Ar1 ! abs(A) -> Au 35 ABS D1Re0,D1Re0 ! abs(B) -> Bu 36$LIDMCUStart: 37 CMP D1Ar1,D1Re0 ! Is ( Au > Bu )? 38 LSR D1Ar3,D1Ar1,#2 ! Calculate (Au & (~3)) >> 2 39 CMPHI D1Re0,D1Ar3 ! OR ( (Au & (~3)) <= (Bu << 2) )? 40 LSLSHI D1Ar3,D1Re0,#1 ! Buq = Bu << 1 41 BLS $LIDMCUSetup ! Yes: Do normal divide 42!! 43!! Quick divide setup can assume that CurBit only needs to start at 2 44!! 45$LIDMCQuick: 46 CMP D1Ar1,D1Ar3 ! ( A >= Buq )? 47 ADDCC D0Re0,D0Re0,#2 ! If yes result += 2 48 SUBCC D1Ar1,D1Ar1,D1Ar3 ! and A -= Buq 49 CMP D1Ar1,D1Re0 ! ( A >= Bu )? 50 ADDCC D0Re0,D0Re0,#1 ! If yes result += 1 51 SUBCC D1Ar1,D1Ar1,D1Re0 ! and A -= Bu 52 ORS D0Ar4,D0Ar4,D0Ar4 ! Return neg result? 53 NEG D0Ar2,D0Re0 ! Calulate neg result 54 MOVMI D0Re0,D0Ar2 ! Yes: Take neg result 55$LIDMCRet: 56 MOV PC,D1RtP 57!! 58!! Setup for general unsigned divide code 59!! 60!! D0Re0 is used to form the result, already set to Zero 61!! D1Re0 is the input Bu value, this gets trashed 62!! D0Ar6 is curbit which is set to 1 at the start and shifted up 63!! D0Ar4 is negative if we should return a negative result 64!! D1Ar1 is the input Au value, eventually this holds the remainder 65!! 66$LIDMCUSetup: 67 CMP D1Ar1,D1Re0 ! Is ( Au < Bu )? 68 MOV D0Ar6,#1 ! Set curbit to 1 69 BCS $LIDMCRet ! Yes: Return 0 remainder Au 70!! 71!! Calculate alignment using FFB instruction 72!! 73 FFB D1Ar5,D1Ar1 ! Find first bit of Au 74 ANDN D1Ar5,D1Ar5,#31 ! Handle exceptional case. 75 ORN D1Ar5,D1Ar5,#31 ! if N bit set, set to 31 76 FFB D1Ar3,D1Re0 ! Find first bit of Bu 77 ANDN D1Ar3,D1Ar3,#31 ! Handle exceptional case. 78 ORN D1Ar3,D1Ar3,#31 ! if N bit set, set to 31 79 SUBS D1Ar3,D1Ar5,D1Ar3 ! calculate diff, ffbA - ffbB 80 MOV D0Ar2,D1Ar3 ! copy into bank 0 81 LSLGT D1Re0,D1Re0,D1Ar3 ! ( > 0) ? left shift B 82 LSLGT D0Ar6,D0Ar6,D0Ar2 ! ( > 0) ? left shift curbit 83!! 84!! Now we start the divide proper, logic is 85!! 86!! if ( A >= B ) add curbit to result and subtract B from A 87!! shift curbit and B down by 1 in either case 88!! 89$LIDMCLoop: 90 CMP D1Ar1, D1Re0 ! ( A >= B )? 91 ADDCC D0Re0, D0Re0, D0Ar6 ! If yes result += curbit 92 SUBCC D1Ar1, D1Ar1, D1Re0 ! and A -= B 93 LSRS D0Ar6, D0Ar6, #1 ! Shift down curbit, is it zero? 94 LSR D1Re0, D1Re0, #1 ! Shift down B 95 BNZ $LIDMCLoop ! Was single bit in curbit lost? 96 ORS D0Ar4,D0Ar4,D0Ar4 ! Return neg result? 97 NEG D0Ar2,D0Re0 ! Calulate neg result 98 MOVMI D0Re0,D0Ar2 ! Yes: Take neg result 99 MOV PC,D1RtP 100 .size ___divsi3,.-___divsi3 101