Merge branch 'vendor/GCC50'
[dragonfly.git] / contrib / binutils-2.24 / gas / doc / c-m32c.texi
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1@c Copyright 2005, 2008
2@c Free Software Foundation, Inc.
3@c This is part of the GAS manual.
4@c For copying conditions, see the file as.texinfo.
5@ifset GENERIC
6@page
7@node M32C-Dependent
8@chapter M32C Dependent Features
9@end ifset
10@ifclear GENERIC
11@node Machine Dependencies
12@chapter M32C Dependent Features
13@end ifclear
14
15@cindex M32C support
16
17@code{@value{AS}} can assemble code for several different members of
18the Renesas M32C family. Normally the default is to assemble code for
19the M16C microprocessor. The @code{-m32c} option may be used to
20change the default to the M32C microprocessor.
21
22@menu
23* M32C-Opts:: M32C Options
24* M32C-Syntax:: M32C Syntax
25@end menu
26
27@node M32C-Opts
28@section M32C Options
29
30@cindex options, M32C
31@cindex M32C options
32
33The Renesas M32C version of @code{@value{AS}} has these
34machine-dependent options:
35
36@table @code
37@item -m32c
38@cindex @samp{-m32c} option, M32C
39@cindex architecture options, M32C
40@cindex M32C architecture option
41Assemble M32C instructions.
42
43@item -m16c
44@cindex @samp{-m16c} option, M16C
45@cindex architecture options, M16C
46@cindex M16C architecture option
47Assemble M16C instructions (default).
48
49@item -relax
50Enable support for link-time relaxations.
51
52@item -h-tick-hex
53Support H'00 style hex constants in addition to 0x00 style.
54
55
56@end table
57
58@node M32C-Syntax
59@section M32C Syntax
60@menu
61* M32C-Modifiers:: Symbolic Operand Modifiers
62* M32C-Chars:: Special Characters
63@end menu
64
65@node M32C-Modifiers
66@subsection Symbolic Operand Modifiers
67
68@cindex M32C modifiers
69@cindex modifiers, M32C
70
71The assembler supports several modifiers when using symbol addresses
72in M32C instruction operands. The general syntax is the following:
73
74@smallexample
75%modifier(symbol)
76@end smallexample
77
78@table @code
79@cindex symbol modifiers
80
81@item %dsp8
82@itemx %dsp16
83
84These modifiers override the assembler's assumptions about how big a
85symbol's address is. Normally, when it sees an operand like
86@samp{sym[a0]} it assumes @samp{sym} may require the widest
87displacement field (16 bits for @samp{-m16c}, 24 bits for
88@samp{-m32c}). These modifiers tell it to assume the address will fit
89in an 8 or 16 bit (respectively) unsigned displacement. Note that, of
90course, if it doesn't actually fit you will get linker errors. Example:
91
92@smallexample
93mov.w %dsp8(sym)[a0],r1
94mov.b #0,%dsp8(sym)[a0]
95@end smallexample
96
97@item %hi8
98
99This modifier allows you to load bits 16 through 23 of a 24 bit
100address into an 8 bit register. This is useful with, for example, the
101M16C @samp{smovf} instruction, which expects a 20 bit address in
102@samp{r1h} and @samp{a0}. Example:
103
104@smallexample
105mov.b #%hi8(sym),r1h
106mov.w #%lo16(sym),a0
107smovf.b
108@end smallexample
109
110@item %lo16
111
112Likewise, this modifier allows you to load bits 0 through 15 of a 24
113bit address into a 16 bit register.
114
115@item %hi16
116
117This modifier allows you to load bits 16 through 31 of a 32 bit
118address into a 16 bit register. While the M32C family only has 24
119bits of address space, it does support addresses in pairs of 16 bit
120registers (like @samp{a1a0} for the @samp{lde} instruction). This
121modifier is for loading the upper half in such cases. Example:
122
123@smallexample
124mov.w #%hi16(sym),a1
125mov.w #%lo16(sym),a0
126@dots{}
127lde.w [a1a0],r1
128@end smallexample
129
130@end table
131
132@node M32C-Chars
133@subsection Special Characters
134
135@cindex line comment character, M32C
136@cindex M32C line comment character
137The presence of a @samp{;} character on a line indicates the start of
138a comment that extends to the end of that line.
139
140If a @samp{#} appears as the first character of a line, the whole line
141is treated as a comment, but in this case the line can also be a
142logical line number directive (@pxref{Comments}) or a
143preprocessor control command (@pxref{Preprocessing}).
144
145@cindex line separator, M32C
146@cindex statement separator, M32C
147@cindex M32C line separator
148The @samp{|} character can be used to separate statements on the same
149line.