+ /* FIXME: However, I'm not convinced that the values that Linux
+ puts in this slot are actually right; specifically, attempting
+ to compile sbcl with sbcl-0.7.7.7 lead to an "infinite SIGTRAP
+ loop" where a (BREAK 16) not in a branch delay slot would have
+ CAUSEF_BD filled. So, we comment
+
+ return (((struct sigcontext *) &(context->uc_mcontext))->sc_cause
+ & CAUSEF_BD);
+
+ out and return 0 always. -- CSR, 2002-09-02 */
+ /* Unfortunately, returning 0 fails for taken branches because
+ os_context_bd_cause is also used to find out if a branch
+ emulation is needed. We work around that by checking if the
+ current instruction is a jump or a branch. */
+ unsigned int inst = *((unsigned int *)(unsigned int)(*os_context_pc_addr(context)));
+
+ switch (inst >> 26) {
+ case 0x0: /* immediate jumps */
+ switch (inst & 0x3f) {
+ case 0x08:
+ case 0x09:
+ return CAUSEF_BD;
+ }
+ break;
+ /* branches and register jumps */
+ case 0x1:
+ case 0x2:
+ case 0x3:
+ case 0x4:
+ case 0x5:
+ case 0x6:
+ case 0x7:
+ return CAUSEF_BD;
+ }
+ return 0;