David Daney <[EMAIL PROTECTED]> writes: > > I am working on a private target where jump instruction patterns are > > similiar to this > > > > jmp <24 bit offset> > > jmp <address register> for 32 bit offsets > > > > if my offset is greater than 24 bits, then i have to move the offset > > to an address register. But inside the branch instruction (in md > > file), i am not able to generate a pseudo register because the > > condition check for "no_new_pseudos " fails. > > > > Can any one suggest a way to overcome this? > > > This is similar to how the MIPS works. Perhaps looking at its > implementation would be useful.
MIPS simply reserves a register, $1. $1 is by convention reserved for use in assembler code. gcc uses it for a long branch. If you can't afford to lose a register, then I think your only option is to pick some callee-saved register and have each branch instruction explicitly clobber it. Then it will be available for use in a long branch, and it will be available for use within a basic block. This is far from ideal, but I don't know a better way to handle it within gcc's current framework. Ian
