| /* |

| * 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 |