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at 2021-04-10T09:24:32-07:00

More cleanups

When installing a breakpoint, we only need to save the single byte.
When removing a breakpoint, we only need to restore the single byte.

+/*

+ * Installs a breakpoint (INT3) at |pc|.  We return the byte that was

+ * replaced by the int3 instruction.

+ */

 unsigned long

 arch_install_breakpoint(void *pc)

 {

     unsigned char* ptr = (unsigned char *) pc;

-    unsigned long result = ptr[0] | (ptr[1] << 8) | (ptr[2] << 16) | (ptr[3] << 24);

+    unsigned long result = *ptr;

     DPRINTF(debug_handlers,

             (stderr, "arch_install_breakpoint at %p, old code = 0x%lx\n",

              pc, result));

-    *(char *) pc = BREAKPOINT_INST;	/* x86 INT3       */

+    *ptr = BREAKPOINT_INST;	/* x86 INT3       */

     return result;

 }

              pc, orig_inst));

     unsigned char *ptr = (unsigned char *) pc;

     /*

-     * Just restore all the bytes from orig_inst.  Should we just

-     * re-install just the one byte that was taken by the int3

-     * instruction?

+     * Just restore the byte from orig_inst.

      */

     ptr[0] = orig_inst & 0xff;

-    ptr[1] = (orig_inst >> 8) & 0xff;

-    ptr[2] = (orig_inst >> 16) & 0xff;

-    ptr[3] = (orig_inst >> 24) & 0xff;

 }

Raymond Toy pushed to branch issue-97-define-ud2-inst at cmucl / cmucl

Commits:

1 changed file:

Changes: