| Using as: Compare-and-branch-i960 |
|---|
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The 960 architectures provide combined Compare-and-Branch instructions that permit you to store the branch target in the lower 13 bits of the instruction word itself. However, if you specify a branch target far enough away that its address won’t fit in 13 bits, the assembler can either issue an error, or convert your Compare-and-Branch instruction into separate instructions to do the compare and the branch.
Whether as gives an error or expands the instruction depends
on two choices you can make: whether you use the ‘-no-relax’ option,
and whether you use a “Compare and Branch” instruction or a “Compare
and Jump” instruction. The “Jump” instructions are always
expanded if necessary; the “Branch” instructions are expanded when
necessary unless you specify -no-relax—in which case
as gives an error instead.
These are the Compare-and-Branch instructions, their “Jump” variants, and the instruction pairs they may expand into: