diff options
| author | Eric Biederman <ebiederm@xmission.com> | 2004-11-18 22:38:08 +0000 |
|---|---|---|
| committer | Eric Biederman <ebiederm@xmission.com> | 2004-11-18 22:38:08 +0000 |
| commit | a9e632c2ac29c60872e7e4f9314263b34ce5031d (patch) | |
| tree | 2a76647833896d68306553c548a65743c87b417e /src/arch/ppc/lib/div64.S | |
| parent | bec8acedf18b4d35f95b4a4c254eb925bd4d53bd (diff) | |
- First stab at getting the ppc ports building and working.
- The sandpointx3+altimus has been consolidated into one directory for now.
- Added support for having different versions of the pci access functions
on a per bus basis if needed.
Hopefully I have not broken something inadvertently.
git-svn-id: svn://svn.coreboot.org/coreboot/trunk@1786 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1
Diffstat (limited to 'src/arch/ppc/lib/div64.S')
| -rw-r--r-- | src/arch/ppc/lib/div64.S | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/src/arch/ppc/lib/div64.S b/src/arch/ppc/lib/div64.S new file mode 100644 index 0000000000..48047747e0 --- /dev/null +++ b/src/arch/ppc/lib/div64.S @@ -0,0 +1,58 @@ +/* + * 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 <ppc_asm.tmpl> + + .globl __div64_32 +__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, + add r9,r4,r10 # rounding up (so the estimate cannot + andc r11,r6,r10 # ever be too large, only too small) + andc r9,r9,r10 + 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 |