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| ;; SPDX-License-Identifier: GPL-2.0-or-later
| ;; Copyright 2010 Free Software Foundation, Inc.
| ;; Contributed by Bernd Schmidt <bernds@codesourcery.com>.
| ;;
|
| #include <linux/linkage.h>
|
| ;; ABI considerations for the divide functions
| ;; The following registers are call-used:
| ;; __c6xabi_divi A0,A1,A2,A4,A6,B0,B1,B2,B4,B5
| ;; __c6xabi_divu A0,A1,A2,A4,A6,B0,B1,B2,B4
| ;; __c6xabi_remi A1,A2,A4,A5,A6,B0,B1,B2,B4
| ;; __c6xabi_remu A1,A4,A5,A7,B0,B1,B2,B4
| ;;
| ;; In our implementation, divu and remu are leaf functions,
| ;; while both divi and remi call into divu.
| ;; A0 is not clobbered by any of the functions.
| ;; divu does not clobber B2 either, which is taken advantage of
| ;; in remi.
| ;; divi uses B5 to hold the original return address during
| ;; the call to divu.
| ;; remi uses B2 and A5 to hold the input values during the
| ;; call to divu. It stores B3 in on the stack.
|
|
| .text
|
| ENTRY(__c6xabi_remu)
| ;; The ABI seems designed to prevent these functions calling each other,
| ;; so we duplicate most of the divsi3 code here.
| mv .s2x A4, B1
| lmbd .l2 1, B4, B1
| || [!B1] b .s2 B3 ; RETURN A
| || [!B1] mvk .d2 1, B4
|
| mv .l1x B1, A7
| || shl .s2 B4, B1, B4
|
| cmpltu .l1x A4, B4, A1
| [!A1] sub .l1x A4, B4, A4
| shru .s2 B4, 1, B4
|
| _remu_loop:
| cmpgt .l2 B1, 7, B0
| || [B1] subc .l1x A4,B4,A4
| || [B1] add .s2 -1, B1, B1
| ;; RETURN A may happen here (note: must happen before the next branch)
| [B1] subc .l1x A4,B4,A4
| || [B1] add .s2 -1, B1, B1
| || [B0] b .s1 _remu_loop
| [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
| [B1] subc .l1x A4,B4,A4
| || [B1] add .s2 -1, B1, B1
| [B1] subc .l1x A4,B4,A4
|
| extu .s1 A4, A7, A4
| nop 2
| ENDPROC(__c6xabi_remu)
|
|
