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| author | Srikant Patnaik | 2015-01-13 15:08:24 +0530 |
|---|---|---|
| committer | Srikant Patnaik | 2015-01-13 15:08:24 +0530 |
| commit | 97327692361306d1e6259021bc425e32832fdb50 (patch) | |
| tree | fe9088f3248ec61e24f404f21b9793cb644b7f01 /arch/powerpc/lib/div64.S | |
| parent | 2d05a8f663478a44e088d122e0d62109bbc801d0 (diff) | |
| parent | a3a8b90b61e21be3dde9101c4e86c881e0f06210 (diff) | |
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dirty fix to merging
Diffstat (limited to 'arch/powerpc/lib/div64.S')
| -rw-r--r-- | arch/powerpc/lib/div64.S | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/arch/powerpc/lib/div64.S b/arch/powerpc/lib/div64.S new file mode 100644 index 00000000..83d9832f --- /dev/null +++ b/arch/powerpc/lib/div64.S @@ -0,0 +1,59 @@ +/* + * Divide a 64-bit unsigned number by a 32-bit unsigned number. + * This routine assumes that the top 32 bits of the dividend are + * non-zero to start with. + * On entry, r3 points to the dividend, which get overwritten with + * the 64-bit quotient, and r4 contains the divisor. + * On exit, r3 contains the remainder. + * + * Copyright (C) 2002 Paul Mackerras, IBM Corp. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ +#include <asm/ppc_asm.h> +#include <asm/processor.h> + +_GLOBAL(__div64_32) + lwz r5,0(r3) # get the dividend into r5/r6 + lwz r6,4(r3) + cmplw r5,r4 + li r7,0 + li r8,0 + blt 1f + divwu r7,r5,r4 # if dividend.hi >= divisor, + mullw r0,r7,r4 # quotient.hi = dividend.hi / divisor + subf. r5,r0,r5 # dividend.hi %= divisor + beq 3f +1: mr r11,r5 # here dividend.hi != 0 + andis. r0,r5,0xc000 + bne 2f + cntlzw r0,r5 # we are shifting the dividend right + li r10,-1 # to make it < 2^32, and shifting + srw r10,r10,r0 # the divisor right the same amount, + addc r9,r4,r10 # rounding up (so the estimate cannot + andc r11,r6,r10 # ever be too large, only too small) + andc r9,r9,r10 + addze r9,r9 + or r11,r5,r11 + rotlw r9,r9,r0 + rotlw r11,r11,r0 + divwu r11,r11,r9 # then we divide the shifted quantities +2: mullw r10,r11,r4 # to get an estimate of the quotient, + mulhwu r9,r11,r4 # multiply the estimate by the divisor, + subfc r6,r10,r6 # take the product from the divisor, + add r8,r8,r11 # and add the estimate to the accumulated + subfe. r5,r9,r5 # quotient + bne 1b +3: cmplw r6,r4 + blt 4f + divwu r0,r6,r4 # perform the remaining 32-bit division + mullw r10,r0,r4 # and get the remainder + add r8,r8,r0 + subf r6,r10,r6 +4: stw r7,0(r3) # return the quotient in *r3 + stw r8,4(r3) + mr r3,r6 # return the remainder in r3 + blr |