| @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 |