projects / thirdparty / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 1a59d1b8 | 1 | ;; SPDX-License-Identifier: GPL-2.0-or-later |
| 09831ca7 AJ |
2 | ;; Copyright 2011 Free Software Foundation, Inc. |
| 3 | ;; Contributed by Bernd Schmidt <bernds@codesourcery.com>. | |
| 4 | ;; | |
| 09831ca7 AJ |
5 | |
| 6 | #include <linux/linkage.h> | |
| 7 | ||
| 8 | .text | |
| 9 | ENTRY(__c6xabi_divremu) | |
| 10 | ;; We use a series of up to 31 subc instructions. First, we find | |
| 11 | ;; out how many leading zero bits there are in the divisor. This | |
| 12 | ;; gives us both a shift count for aligning (shifting) the divisor | |
| 13 | ;; to the, and the number of times we have to execute subc. | |
| 14 | ||
| 15 | ;; At the end, we have both the remainder and most of the quotient | |
| 16 | ;; in A4. The top bit of the quotient is computed first and is | |
| 17 | ;; placed in A2. | |
| 18 | ||
| 19 | ;; Return immediately if the dividend is zero. Setting B4 to 1 | |
| 20 | ;; is a trick to allow us to leave the following insns in the jump | |
| 21 | ;; delay slot without affecting the result. | |
| 22 | mv .s2x A4, B1 | |
| 23 | ||
| 24 | [b1] lmbd .l2 1, B4, B1 | |
| 25 | ||[!b1] b .s2 B3 ; RETURN A | |
| 26 | ||[!b1] mvk .d2 1, B4 | |
| 27 | ||
| 28 | ||[!b1] zero .s1 A5 | |
| 29 | mv .l1x B1, A6 | |
| 30 | || shl .s2 B4, B1, B4 | |
| 31 | ||
| 32 | ;; The loop performs a maximum of 28 steps, so we do the | |
| 33 | ;; first 3 here. | |
| 34 | cmpltu .l1x A4, B4, A2 | |
| 35 | [!A2] sub .l1x A4, B4, A4 | |
| 36 | || shru .s2 B4, 1, B4 | |
| 37 | || xor .s1 1, A2, A2 | |
| 38 | ||
| 39 | shl .s1 A2, 31, A2 | |
| 40 | || [b1] subc .l1x A4,B4,A4 | |
| 41 | || [b1] add .s2 -1, B1, B1 | |
| 42 | [b1] subc .l1x A4,B4,A4 | |
| 43 | || [b1] add .s2 -1, B1, B1 | |
| 44 | ||
| 45 | ;; RETURN A may happen here (note: must happen before the next branch) | |
| 46 | __divremu0: | |
| 47 | cmpgt .l2 B1, 7, B0 | |
| 48 | || [b1] subc .l1x A4,B4,A4 | |
| 49 | || [b1] add .s2 -1, B1, B1 | |
| 50 | [b1] subc .l1x A4,B4,A4 | |
| 51 | || [b1] add .s2 -1, B1, B1 | |
| 52 | || [b0] b .s1 __divremu0 | |
| 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 | [b1] subc .l1x A4,B4,A4 | |
| 62 | || [b1] add .s2 -1, B1, B1 | |
| 63 | ;; loop backwards branch happens here | |
| 64 | ||
| 65 | ret .s2 B3 | |
| 66 | || mvk .s1 32, A1 | |
| 67 | sub .l1 A1, A6, A6 | |
| 68 | || extu .s1 A4, A6, A5 | |
| 69 | shl .s1 A4, A6, A4 | |
| 70 | shru .s1 A4, 1, A4 | |
| 71 | || sub .l1 A6, 1, A6 | |
| 72 | or .l1 A2, A4, A4 | |
| 73 | shru .s1 A4, A6, A4 | |
| 74 | nop | |
| 75 | ENDPROC(__c6xabi_divremu) |