Compare-and-branch-i960 - Using as
Description: Using as

Previous: callj-i960, Up: Opcodes for i960

##### 9.17.4.2 Compare-and-Branch

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: