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comparison gcc/config/cris/cris-modes.def @ 152:2b5abeee2509

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update gcc11
author anatofuz
date Mon, 25 May 2020 07:50:57 +0900
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145:1830386684a0 152:2b5abeee2509
1 /* Definitions of target machine for GNU compiler, for CRIS.
2 Copyright (C) 2002-2020 Free Software Foundation, Inc.
3
4 This file is part of GCC.
5
6 GCC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3, or (at your option)
9 any later version.
10
11 GCC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
19
20 /* Node: Condition Code */
21
22 /* The mode used for condition-codes depends on both the way the
23 condition-codes are generated (the CC-setter, typically the compare
24 instruction), and used (the CC-user, typically a branch). For CRIS, we
25 have ordinary compares and incidental condition-code settings from
26 preceding instructions, setting a subset of N, Z, V and C to usable
27 values, from the perspective of comparing the result against zero
28 (fpcraz). The two subsets meaningful to gcc are all of N, Z, V, C
29 versus just N, Z; some CC-users care only about N and/or Z and some
30 that care about at least one of those flags together with V and/or C.
31
32 The plain "CC_MODE (CC)" (which is always present in gcc), is used to
33 reflect the "unoptimized" state, where the CC-setter is a compare
34 against zero and the CC-user is any branch or s<condition> instruction,
35 before reload. After reload, a need for C or V is reflected as
36 CC_NZVCmode in both setters and users, and others remain CCmode, until
37 or if optimization of CC-setter and CC-users, when CCmode setters can
38 be changed or replaced by either CC_NZmode or CC_NZVCmode. To wit, all
39 users that require CC_NZVCmode must match only that mode at any time.
40 All other users must match all CCmodes. All setters that set only
41 CC_NZmode must set only that mode. All other setters must match
42 setting all CCmodes. */
43
44 /* Z and N flags only. For a condition-code setter: only the Z and N
45 flags are set to usable values, fpcraz. For a condition-code user: the
46 operation using the condition codes only care about the Z and N flags. */
47 CC_MODE (CC_NZ);
48
49 /* Z and N *and* V and C flags. For a condition-code setter: all flags
50 are set to usable values, fpcraz. For a condition-code user: at least
51 one of V and C are used and possibly N and Z too. */
52 CC_MODE (CC_NZVC);
53
54 /* The result of a btst / btstq instruction for extracting a single bit
55 goes negated into the N flag, or in olde cc0-parlance, CC_Z_IN_NOT_N. */
56 CC_MODE (CC_ZnN);