Using as: CR16 Operand Qualifiers

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#### 9.7.1 CR16 Operand Qualifiers

The National Semiconductor CR16 target of `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 `@` is required. CR16 architecture uses one of the following expression qualifiers:

`s`

  - `Specifies expression operand type as small`

`m`

  - `Specifies expression operand type as medium`

`l`

  - `Specifies expression operand type as large`

`c`

  - `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.`

`got/GOT`

  - `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`

`cgot/cGOT`

  - `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.`

CR16 target operand qualifiers and its size (in bits):

‘`Immediate Operand: s`’

  4 bits.

‘`Immediate Operand: m`’

  16 bits, for movb and movw instructions.

‘`Immediate Operand: m`’

  20 bits, movd instructions.

‘`Immediate Operand: l`’

  32 bits.

‘`Absolute Operand: s`’

  Illegal specifier for this operand.

‘`Absolute Operand: m`’

  20 bits, movd instructions.

‘`Displacement Operand: s`’

  8 bits.

‘`Displacement Operand: m`’

  16 bits.

‘`Displacement Operand: l`’

  24 bits.

For example:

    1   movw $_myfun@c,r1

        This loads the address of _myfun, shifted right by 1, into r1.

    2   movd $_myfun@c,(r2,r1)

        This loads the address of _myfun, shifted right by 1, into register-pair r2-r1.

    3   _myfun_ptr:
        .long _myfun@c
        loadd _myfun_ptr, (r1,r0)
        jal (r1,r0)

        This .long directive, the address of _myfunc, shifted right by 1 at link time.

    4   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   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.

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