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| ;; SPDX-License-Identifier: GPL-2.0-or-later
| ;; Copyright 2011 Free Software Foundation, Inc.
| ;; Contributed by Bernd Schmidt <bernds@codesourcery.com>.
| ;;
|
| #include <linux/linkage.h>
|
| .text
| ENTRY(__c6xabi_divremu)
| ;; We use a series of up to 31 subc instructions. First, we find
| ;; out how many leading zero bits there are in the divisor. This
| ;; gives us both a shift count for aligning (shifting) the divisor
| ;; to the, and the number of times we have to execute subc.
|
| ;; At the end, we have both the remainder and most of the quotient
| ;; in A4. The top bit of the quotient is computed first and is
| ;; placed in A2.
|
| ;; Return immediately if the dividend is zero. Setting B4 to 1
| ;; is a trick to allow us to leave the following insns in the jump
| ;; delay slot without affecting the result.
| mv .s2x A4, B1
|
| [b1] lmbd .l2 1, B4, B1
| ||[!b1] b .s2 B3 ; RETURN A
| ||[!b1] mvk .d2 1, B4
|
| ||[!b1] zero .s1 A5
| mv .l1x B1, A6
| || shl .s2 B4, B1, B4
|
| ;; The loop performs a maximum of 28 steps, so we do the
| ;; first 3 here.
| cmpltu .l1x A4, B4, A2
| [!A2] sub .l1x A4, B4, A4
| || shru .s2 B4, 1, B4
| || xor .s1 1, A2, A2
|
| shl .s1 A2, 31, A2
| || [b1] subc .l1x A4,B4,A4
| || [b1] add .s2 -1, B1, B1
| [b1] subc .l1x A4,B4,A4
| || [b1] add .s2 -1, B1, B1
|
| ;; RETURN A may happen here (note: must happen before the next branch)
| __divremu0:
| cmpgt .l2 B1, 7, B0
| || [b1] subc .l1x A4,B4,A4
| || [b1] add .s2 -1, B1, B1
| [b1] subc .l1x A4,B4,A4
| || [b1] add .s2 -1, B1, B1
| || [b0] b .s1 __divremu0
| [b1] subc .l1x A4,B4,A4
| || [b1] add .s2 -1, B1, B1
| [b1] subc .l1x A4,B4,A4
| || [b1] add .s2 -1, B1, B1
| [b1] subc .l1x A4,B4,A4
| || [b1] add .s2 -1, B1, B1
| [b1] subc .l1x A4,B4,A4
| || [b1] add .s2 -1, B1, B1
| [b1] subc .l1x A4,B4,A4
| || [b1] add .s2 -1, B1, B1
| ;; loop backwards branch happens here
|
| ret .s2 B3
| || mvk .s1 32, A1
| sub .l1 A1, A6, A6
| || extu .s1 A4, A6, A5
| shl .s1 A4, A6, A4
| shru .s1 A4, 1, A4
| || sub .l1 A6, 1, A6
| or .l1 A2, A4, A4
| shru .s1 A4, A6, A4
| nop
| ENDPROC(__c6xabi_divremu)
|
|
