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@c Copyright 2007, 2008 Free Software Foundation, Inc.
@c This is part of the GAS manual.
@c For copying conditions, see the file as.texinfo.
@ifset GENERIC
@page
@node CR16-Dependent
@chapter CR16 Dependent Features
@end ifset
@ifclear GENERIC
@node Machine Dependencies
@chapter CR16 Dependent Features
@end ifclear
@cindex CR16 support
@menu
* CR16 Operand Qualifiers:: CR16 Machine Operand Qualifiers
@end menu
@node CR16 Operand Qualifiers
@section CR16 Operand Qualifiers
@cindex CR16 Operand Qualifiers
The National Semiconductor CR16 target of @code{@value{AS}} has a few machine dependent operand qualifiers.
Operand 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:
@table @code
@item s
- @code{Specifies expression operand type as small}
@item m
- @code{Specifies expression operand type as medium}
@item l
- @code{Specifies expression operand type as large}
@item c
- @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.}
@item got/GOT
- @code{Specifies the CR16 Assembler generates a relocation entry for the operand, offset from Global Offset Table. The linker uses this relocation entry to update the operand address at link time}
@item cgot/cGOT
- @code{Specifies the CompactRISC 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.}
@end table
CR16 target operand qualifiers and its size (in bits):
@table @samp
@item Immediate Operand
- s ---- 4 bits
@item
- m ---- 16 bits, for movb and movw instructions.
@item
- m ---- 20 bits, movd instructions.
@item
- l ---- 32 bits
@item Absolute Operand
- s ---- Illegal specifier for this operand.
@item
- m ---- 20 bits, movd instructions.
@item Displacement Operand
- s ---- 8 bits
@item
- m ---- 16 bits
@item
- l ---- 24 bits
@end table
For example:
@example
1 @code{movw $_myfun@@c,r1}
This loads the address of _myfun, shifted right by 1, into r1.
2 @code{movd $_myfun@@c,(r2,r1)}
This loads the address of _myfun, shifted right by 1, into register-pair r2-r1.
3 @code{_myfun_ptr:}
@code{.long _myfun@@c}
@code{loadd _myfun_ptr, (r1,r0)}
@code{jal (r1,r0)}
This .long directive, the address of _myfunc, shifted right by 1 at link time.
4 @code{loadd _data1@@GOT(r12), (r1,r0)}
This loads the address of _data1, into global offset table (ie GOT) and its offset value from GOT loads into register-pair r2-r1.
5 @code{loadd _myfunc@@cGOT(r12), (r1,r0)}
This loads the address of _myfun, shifted right by 1, into global offset table (ie GOT) and its offset value from GOT loads into register-pair r1-r0.
@end example
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