Special Cases

This topic lists the following special cases for enforce operators:

1. Constants which do not fit. Constants which do not fit can be split in 2 case:
   • Constants which are truncated and an warning may be raised:

     Example, ASR.B D1 , opr24(var3) ,(oprs9(0x3E8), Y)

     The number 0x3E8 doesn’t fit into 9-bit field. This value is truncated to 0xE8

   • Constants which can’t be adapted to the wished addressing mode (selected by the enforce operator) and the compiler raise an error. Here we have 2 special cases:
     • sxe4

       Example, ADD D1, #sxe4i(-7)

     • Unsigned operators

       Example, ADD D2, (opru4(-6), X)

2. Immediate forced to wrong size. In this case the compiler exits with an error. Example,

    LD D7, #opr8i(0x500)

3. Variable address forced to unaccepted addressing mode for that instruction. This case also ends with a compiler error.Example,

    ADD D2, opr24a(var)

4. Shift instructions – when the number of bit positions to shift the operand is forced to #sxe4i(value). This addressing mode is accepted, but is transformed into #imm5i according to the architecture manual. Example,

    ASL.B D3 , (-X)  ,#sxe4i(2) is transformed in the compiler into
    ASL.B D3 , (-X)  ,#opr5i(2)