Index: vm_exec.c
===================================================================
--- vm_exec.c	(revision 46565)
+++ vm_exec.c	(working copy)
@@ -24,6 +24,9 @@
 #elif defined(__GNUC__) && defined(__i386__)
 #define DECL_SC_REG(type, r, reg) register type reg_##r __asm__("e" reg)
 
+#elif defined(__GNUC__) && defined(__powerpc64__)
+#define DECL_SC_REG(type, r, reg) register type reg_##r __asm__("r" reg)
+
 #else
 #define DECL_SC_REG(type, r, reg) register type reg_##r
 #endif
@@ -70,6 +73,11 @@
 # endif
 #define USE_MACHINE_REGS 1
 
+#elif defined(__GNUC__) && defined(__powerpc64__)
+    DECL_SC_REG(VALUE *, pc, "14");
+    DECL_SC_REG(rb_control_frame_t *, cfp, "15");
+#define USE_MACHINE_REGS 1
+
 #else
     register rb_control_frame_t *reg_cfp;
     VALUE *reg_pc;