| David Brazdil | 0f672f6 | 2019-12-10 10:32:29 +0000 | [diff] [blame^] | 1 | ;; SPDX-License-Identifier: GPL-2.0-or-later |
| Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 2 | ;; Copyright 2010 Free Software Foundation, Inc. |
| 3 | ;; Contributed by Bernd Schmidt <bernds@codesourcery.com>. |
| 4 | ;; |
| Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 5 | |
| 6 | #include <linux/linkage.h> |
| 7 | |
| 8 | ;; ABI considerations for the divide functions |
| 9 | ;; The following registers are call-used: |
| 10 | ;; __c6xabi_divi A0,A1,A2,A4,A6,B0,B1,B2,B4,B5 |
| 11 | ;; __c6xabi_divu A0,A1,A2,A4,A6,B0,B1,B2,B4 |
| 12 | ;; __c6xabi_remi A1,A2,A4,A5,A6,B0,B1,B2,B4 |
| 13 | ;; __c6xabi_remu A1,A4,A5,A7,B0,B1,B2,B4 |
| 14 | ;; |
| 15 | ;; In our implementation, divu and remu are leaf functions, |
| 16 | ;; while both divi and remi call into divu. |
| 17 | ;; A0 is not clobbered by any of the functions. |
| 18 | ;; divu does not clobber B2 either, which is taken advantage of |
| 19 | ;; in remi. |
| 20 | ;; divi uses B5 to hold the original return address during |
| 21 | ;; the call to divu. |
| 22 | ;; remi uses B2 and A5 to hold the input values during the |
| 23 | ;; call to divu. It stores B3 in on the stack. |
| 24 | |
| 25 | |
| 26 | .text |
| 27 | |
| 28 | ENTRY(__c6xabi_remu) |
| 29 | ;; The ABI seems designed to prevent these functions calling each other, |
| 30 | ;; so we duplicate most of the divsi3 code here. |
| 31 | mv .s2x A4, B1 |
| 32 | lmbd .l2 1, B4, B1 |
| 33 | || [!B1] b .s2 B3 ; RETURN A |
| 34 | || [!B1] mvk .d2 1, B4 |
| 35 | |
| 36 | mv .l1x B1, A7 |
| 37 | || shl .s2 B4, B1, B4 |
| 38 | |
| 39 | cmpltu .l1x A4, B4, A1 |
| 40 | [!A1] sub .l1x A4, B4, A4 |
| 41 | shru .s2 B4, 1, B4 |
| 42 | |
| 43 | _remu_loop: |
| 44 | cmpgt .l2 B1, 7, B0 |
| 45 | || [B1] subc .l1x A4,B4,A4 |
| 46 | || [B1] add .s2 -1, B1, B1 |
| 47 | ;; RETURN A may happen here (note: must happen before the next branch) |
| 48 | [B1] subc .l1x A4,B4,A4 |
| 49 | || [B1] add .s2 -1, B1, B1 |
| 50 | || [B0] b .s1 _remu_loop |
| 51 | [B1] subc .l1x A4,B4,A4 |
| 52 | || [B1] add .s2 -1, B1, B1 |
| 53 | [B1] subc .l1x A4,B4,A4 |
| 54 | || [B1] add .s2 -1, B1, B1 |
| 55 | [B1] subc .l1x A4,B4,A4 |
| 56 | || [B1] add .s2 -1, B1, B1 |
| 57 | [B1] subc .l1x A4,B4,A4 |
| 58 | || [B1] add .s2 -1, B1, B1 |
| 59 | [B1] subc .l1x A4,B4,A4 |
| 60 | || [B1] add .s2 -1, B1, B1 |
| 61 | ;; loop backwards branch happens here |
| 62 | |
| 63 | ret .s2 B3 |
| 64 | [B1] subc .l1x A4,B4,A4 |
| 65 | || [B1] add .s2 -1, B1, B1 |
| 66 | [B1] subc .l1x A4,B4,A4 |
| 67 | |
| 68 | extu .s1 A4, A7, A4 |
| 69 | nop 2 |
| 70 | ENDPROC(__c6xabi_remu) |