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as: CR16 Operand Qualifiers

 
 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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