-/* md_codegen_patch_branch *****************************************************
-
- Back-patches a branch instruction.
-
-*******************************************************************************/
-
-void md_codegen_patch_branch(codegendata *cd, s4 branchmpc, s4 targetmpc)
-{
- s4 *mcodeptr;
- s4 mcode;
- s4 disp; /* branch displacement */
-
- /* calculate the patch position */
-
- mcodeptr = (s4 *) (cd->mcodebase + branchmpc);
-
- /* get the instruction before the exception point */
-
- mcode = mcodeptr[-1];
-
- /* Calculate the branch displacement. */
-
- disp = targetmpc - branchmpc + 4;
-
- /* Check which branch instruction we have. Then mask it and patch
- the displacement. */
-
- if ((mcode & 0xfc000000) == 0x48000000) {
- /* bx (0x48000000) */
-
- if ((disp < (s4) 0xfe000000) || (disp > (s4) 0x01fffffc))
- vm_abort("md_codegen_patch_branch: branch displacement out of range: %d > +/-%d", disp, 0x03fffffc);
-
- mcode &= ~M_BMASK; /* mask out previous displacement, probably +4 */
- mcode |= (disp & M_BMASK);
- }
- else if ((mcode & 0xfc000000) == 0x40000000) {
- /* bcx (0x40000000) */
-
- if ((disp < (s4) 0xffff8000) || (disp > (s4) 0x00007fff))
- vm_abort("md_codegen_patch_branch: branch displacement out of range: %d > +/-%d", disp, 0x00007fff);
-
- mcode &= ~M_BCMASK; /* mask out previous displacement, probably +4 */
- mcode |= (disp & M_BCMASK);
- }
- else
- vm_abort("md_codegen_patch_branch: unknown instruction 0x%08x", mcode);
-
- /* patch the branch instruction before the mcodeptr */
-
- mcodeptr[-1] = mcode;
-}
-
-