Mercurial > hg > CbC > CbC_gcc
comparison gcc/config/pdp11/pdp11-modes.def @ 131:84e7813d76e9
gcc-8.2
author | mir3636 |
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date | Thu, 25 Oct 2018 07:37:49 +0900 |
parents | 04ced10e8804 |
children | 1830386684a0 |
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111:04ced10e8804 | 131:84e7813d76e9 |
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1 /* Definitions of target machine for GNU compiler, for the pdp-11 | 1 /* Definitions of target machine for GNU compiler, for the pdp-11 |
2 Copyright (C) 2002-2017 Free Software Foundation, Inc. | 2 Copyright (C) 2002-2018 Free Software Foundation, Inc. |
3 Contributed by Michael K. Gschwind (mike@vlsivie.tuwien.ac.at). | 3 Contributed by Michael K. Gschwind (mike@vlsivie.tuwien.ac.at). |
4 | 4 |
5 This file is part of GCC. | 5 This file is part of GCC. |
6 | 6 |
7 GCC is free software; you can redistribute it and/or modify | 7 GCC is free software; you can redistribute it and/or modify |
17 You should have received a copy of the GNU General Public License | 17 You should have received a copy of the GNU General Public License |
18 along with GCC; see the file COPYING3. If not see | 18 along with GCC; see the file COPYING3. If not see |
19 <http://www.gnu.org/licenses/>. */ | 19 <http://www.gnu.org/licenses/>. */ |
20 | 20 |
21 /* Add any extra modes needed to represent the condition code. | 21 /* Add any extra modes needed to represent the condition code. |
22 CCFPmode is used for FPU, but should we use a separate reg? */ | |
23 | 22 |
24 CC_MODE (CCFP); | 23 The default CCmode is the CPU condition codes, as set by compare; |
24 all conditional branches are valid with this. | |
25 | |
26 CCNZmode is the CPU condition code as a side effect of arithmetic | |
27 or logic operations where N and Z reflect sign and zero status of | |
28 the result, but the V bit is not meaningful. Unsigned conditional | |
29 branches don't apply then (no such thing when comparing with zero) | |
30 and signed branches that use V need to clear V first if they are to | |
31 be used. CCNZ mode appears in side effects (implicit compare with | |
32 zero) if V is not forced to 0 by the instruction. In such cases, V | |
33 often reflects signed overflow of the operation, which means a | |
34 signed branch will get the sign backwards. This applies both to | |
35 some float and integer operations. | |
36 | |
37 These modes are used both in the FPU and the CPU, since they have | |
38 the same meaning, and also because the FPU condition codes are | |
39 copied to the CPU before being used in conditional branches. */ | |
40 | |
41 CC_MODE (CCNZ); | |
42 | |
25 RESET_FLOAT_FORMAT (SF, pdp11_f_format); | 43 RESET_FLOAT_FORMAT (SF, pdp11_f_format); |
26 RESET_FLOAT_FORMAT (DF, pdp11_d_format); | 44 RESET_FLOAT_FORMAT (DF, pdp11_d_format); |