Chapter 5. Machine Dependent Features

ld has additional features on some platforms; the following sections describe them. Machines where ld has no additional functionality are not listed.

5.1. ld and the H8/300

For the H8/300, ld can perform these global optimizations when you specify the -relax command-line option.

relaxing address modes

ld finds all jsr and jmp instructions whose targets are within eight bits, and turns them into eight-bit program-counter relative bsr and bra instructions, respectively.

synthesizing instructions

ld finds all mov.b instructions which use the sixteen-bit absolute address form, but refer to the top page of memory, and changes them to use the eight-bit address form. (That is: the linker turns mov.b @aa:16 into mov.b @aa:8 whenever the address aa is in the top page of memory).