Node: H8/300, Next: i960, Up: Machine Dependent
ld
and the H8/300For the H8/300, ld
can perform these global optimizations when you specify the --relax
command-line option.
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.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).