1@c Copyright 2007 Free Software Foundation, Inc.
2@c This is part of the GAS manual.
3@c For copying conditions, see the file as.texinfo.
4
5@ifset GENERIC
6@page
7@node CR16-Dependent
8@chapter CR16 Dependent Features
9@end ifset
10@ifclear GENERIC
11@node Machine Dependencies
12@chapter CR16 Dependent Features
13@end ifclear
14
15@cindex CR16 support
16@menu
17* CR16 Operand Qualifiers::     CR16 Machine Operand Qualifiers
18@end menu
19
20@node CR16 Operand Qualifiers
21@section CR16 Operand Qualifiers
22@cindex CR16 Operand Qualifiers
23
24The National Semiconductor CR16 target of @code{@value{AS}} has a few machine dependent operand qualifiers.  
25
26Operand expression type qualifier is an optional field in the instruction operand, to determines the type of the expression field of an operand. The @code{@@} is required. CR16 architecture uses one of the following expression qualifiers:
27
28@table @code
29@item  s 
30- @code{Specifies expression operand type as small}
31@item  m 
32- @code{Specifies expression operand type as medium}
33@item  l 
34- @code{Specifies expression operand type as large}
35@item  c 
36- @code{Specifies the CR16 Assembler generates a relocation entry for the operand, where pc has implied bit, the expression is adjusted accordingly. The linker uses the relocation entry to update the operand address at link time.}
37@end table
38
39CR16 target operand qualifiers and its size (in bits):
40
41@table @samp
42@item Immediate Operand
43- s ---- 4 bits
44@item 
45- m ---- 16 bits, for movb and movw instructions.
46@item 
47- m ---- 20 bits, movd instructions.
48@item 
49- l ---- 32 bits
50
51@item Absolute Operand
52- s ---- Illegal specifier for this operand.
53@item  
54- m ---- 20 bits, movd instructions.
55
56@item Displacement Operand
57- s ---- 8 bits
58@item
59- m ---- 16 bits
60@item 
61- l ---- 24 bits
62@end table
63
64For example:
65@example
661   @code{movw $_myfun@@c,r1}
67
68    This loads the address of _myfun, shifted right by 1, into r1.
69
702   @code{movd $_myfun@@c,(r2,r1)}
71
72    This loads the address of _myfun, shifted right by 1, into register-pair r2-r1.
73                
743   @code{_myfun_ptr:}
75    @code{.long _myfun@@c}
76    @code{loadd _myfun_ptr, (r1,r0)}
77    @code{jal (r1,r0)}
78
79    This .long directive, the address of _myfunc, shifted right by 1 at link time.
80@end example
81