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41acf796 | 1 | @c Copyright (C) 1991, 92-98, 1999 Free Software Foundation, Inc. |
252b5132 RH |
2 | @c This is part of the GAS manual. |
3 | @c For copying conditions, see the file as.texinfo. | |
4 | @ifset GENERIC | |
5 | @page | |
6 | @node M32R-Dependent | |
7 | @chapter M32R Dependent Features | |
8 | @end ifset | |
9 | @ifclear GENERIC | |
10 | @node Machine Dependencies | |
11 | @chapter M32R Dependent Features | |
12 | @end ifclear | |
13 | ||
41acf796 DE |
14 | @cindex M32R support |
15 | @menu | |
16 | * M32R-Opts:: M32R Options | |
17 | * M32R-Warnings:: M32R Warnings | |
18 | @end menu | |
19 | ||
20 | @node M32R-Opts | |
21 | @section M32R Options | |
22 | ||
23 | @cindex options, M32R | |
24 | @cindex M32R options | |
25 | ||
26 | The Mitsubishi M32R version of @code{@value{AS}} has a few machine | |
27 | dependent options: | |
28 | ||
29 | @table @code | |
30 | @item -m32rx | |
31 | @cindex @samp{-m32rx} option, M32RX | |
32 | @cindex architecture options, M32RX | |
33 | @cindex M32R architecture options | |
34 | @code{@value{AS}} can assemble code for several different members of the | |
35 | Mitsubishi M32R family. Normally the default is to assemble code for | |
36 | the M32R microprocessor. This option may be used to change the default | |
37 | to the M32RX microprocessor, which adds some more instructions to the | |
38 | basic M32R instruction set, and some additional parameters to some of | |
39 | the original instructions. | |
40 | ||
41 | @item -warn-explicit-parallel-conflicts | |
42 | @cindex @samp{-warn-explicit-parallel-conflicts} option, M32RX | |
43 | Instructs @code{@value{AS}} to produce warning messages when | |
44 | questionable parallel instructions are encountered. This option is | |
45 | enabled by default, but @code{@value{GCC}} disables it when it invokes | |
46 | @code{@value{AS}} directly. Questionable instructions are those whoes | |
47 | behaviour would be different if they were executed sequentially. For | |
48 | example the code fragment @samp{mv r1, r2 || mv r3, r1} produces a | |
49 | different result from @samp{mv r1, r2 \n mv r3, r1} since the former | |
50 | moves r1 into r3 and then r2 into r1, whereas the later moves r2 into r1 | |
51 | and r3. | |
52 | ||
53 | @item -Wp | |
54 | @cindex @samp{-Wp} option, M32RX | |
55 | This is a shorter synonym for the @emph{-warn-explicit-parallel-conflicts} | |
56 | option. | |
57 | ||
58 | @item -no-warn-explicit-parallel-conflicts | |
59 | @cindex @samp{-no-warn-explicit-parallel-conflicts} option, M32RX | |
60 | Instructs @code{@value{AS}} not to produce warning messages when | |
61 | questionable parallel instructions are encountered. | |
62 | ||
63 | @item -Wnp | |
64 | @cindex @samp{-Wnp} option, M32RX | |
65 | This is a shorter synonym for the @emph{-no-warn-explicit-parallel-conflicts} | |
66 | option. | |
67 | ||
68 | @end table | |
69 | ||
70 | @node M32R-Warnings | |
71 | @section M32R Warnings | |
72 | ||
73 | @cindex warnings, M32R | |
74 | @cindex M32R warnings | |
75 | ||
76 | There are several warning and error messages that can be produced by | |
77 | @code{@value{AS}} which are specific to the M32R: | |
78 | ||
79 | @table @code | |
80 | ||
81 | @item output of 1st instruction is the same as an input to 2nd instruction - is this intentional ? | |
82 | This message is only produced if warnings for explicit parallel | |
83 | conflicts have been enabled. It indicates that the assembler has | |
84 | encountered a parallel instruction in which the destination register of | |
85 | the left hand instruction is used as an input register in the right hand | |
86 | instruction. For example in this code fragment | |
87 | @samp{mv r1, r2 || neg r3, r1} register r1 is the destination of the | |
88 | move instruction and the input to the neg instruction. | |
89 | ||
90 | @item output of 2nd instruction is the same as an input to 1st instruction - is this intentional ? | |
91 | This message is only produced if warnings for explicit parallel | |
92 | conflicts have been enabled. It indicates that the assembler has | |
93 | encountered a parallel instruction in which the destination register of | |
94 | the right hand instruction is used as an input register in the left hand | |
95 | instruction. For example in this code fragment | |
96 | @samp{mv r1, r2 || neg r2, r3} register r2 is the destination of the | |
97 | neg instruction and the input to the move instruction. | |
98 | ||
99 | @item instruction @samp{...} is for the M32RX only | |
100 | This message is produced when the assembler encounters an instruction | |
101 | which is only supported by the M32Rx processor, and the @samp{-m32rx} | |
102 | command line flag has not been specified to allow assembly of such | |
103 | instructions. | |
104 | ||
105 | @item unknown instruction @samp{...} | |
106 | This message is produced when the assembler encounters an instruction | |
107 | which it doe snot recognise. | |
108 | ||
109 | @item only the NOP instruction can be issued in parallel on the m32r | |
110 | This message is produced when the assembler encounters a parallel | |
111 | instruction which does not involve a NOP instruction and the | |
112 | @samp{-m32rx} command line flag has not been specified. Only the M32Rx | |
113 | processor is able to execute two instructions in parallel. | |
114 | ||
115 | @item instruction @samp{...} cannot be executed in parallel. | |
116 | This message is produced when the assembler encounters a parallel | |
117 | instruction which is made up of one or two instructions which cannot be | |
118 | executed in parallel. | |
119 | ||
120 | @item Instructions share the same execution pipeline | |
121 | This message is produced when the assembler encounters a parallel | |
122 | instruction whoes components both use the same execution pipeline. | |
123 | ||
124 | @item Instructions write to the same destination register. | |
125 | This message is produced when the assembler encounters a parallel | |
126 | instruction where both components attempt to modify the same register. | |
127 | For example these code fragments will produce this message: | |
128 | @samp{mv r1, r2 || neg r1, r3} | |
129 | @samp{jl r0 || mv r14, r1} | |
130 | @samp{st r2, @@-r1 || mv r1, r3} | |
131 | @samp{mv r1, r2 || ld r0, @@r1+} | |
132 | @samp{cmp r1, r2 || addx r3, r4} (Both write to the condition bit) | |
133 | ||
134 | @end table |