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8.1.2.3 Register Names

General-purpose registers are represented by predefined symbols of the form GRnnn (for global registers) or LRnnn (for local registers), where nnn represents a number between 0 and 127, written with no leading zeros. The leading letters may be in either upper or lower case; for example, gr13 and LR7 are both valid register names.

You may also refer to general-purpose registers by specifying the register number as the result of an expression (prefixed with %% to flag the expression as a register number):

     %%expression

—where expression must be an absolute expression evaluating to a number between 0 and 255. The range [0, 127] refers to global registers, and the range [128, 255] to local registers.

In addition, as understands the following protected special-purpose register names for the AMD 29K family:

       vab    chd    pc0
       ops    chc    pc1
       cps    rbp    pc2
       cfg    tmc    mmu
       cha    tmr    lru

These unprotected special-purpose register names are also recognized:

       ipc    alu    fpe
       ipa    bp     inte
       ipb    fc     fps
       q      cr     exop