diff --git a/ChangeLog b/ChangeLog
index cbfbafd60..0a4b57367 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,27 @@
+2012-12-11 Paulo Andrade <pcpa@gnu.org>
+
+	* configure.ac: Only default to using the builtin disassembler
+	if on GNU/Linux. This should be temporary, due to requiring
+	/proc/self/exe.
+	  Correctly check $target_cpu for powerpc.
+
+	* include/lightning/jit_ppc.h: Correctly implement jit_v_num.
+
+	* include/lightning/jit_private.h: Declare proper prototype
+	for jit_init_debug and jit_finish_debug.
+
+	* lib/jit_ppc-cpu.c: Remove code to save/restore callee save
+	float registers, as it is not required since those float
+	registers are not usable currently.
+	  Change prolog and epilog generation to, at least comparing
+	code, match what gcc generates in "gcc -O0", but it is still
+	failing in Darwin PPC, apparently due to the __clear_cache
+	call not being enough, as frequently it will also fail to
+	execute, and the code buffer is all zeroes.
+
+	* lib/lightning.c: Do not fail in jit_regset_scan1 calls due
+	to passing 64 as argument on computers with 64 registers.
+
 2012-12-10 Paulo Andrade <pcpa@gnu.org>
 
 	* lib/jit_mips-cpu.c: Correct all current test cases.
diff --git a/configure.ac b/configure.ac
index e7051c721..920feedc0 100644
--- a/configure.ac
+++ b/configure.ac
@@ -53,7 +53,10 @@ if test "x$DISASSEMBLER" != "xno"; then
 fi
 AM_CONDITIONAL(with_disassembler, [test "x$DISASSEMBLER" != "xno"])
 if test "x$DISASSEMBLER" != "xno"; then
-    LIGHTNING_CFLAGS="$LIGHTNING_CFLAGS -DDISASSEMBLER=1"
+    case "$target_os" in
+	*linux*) LIGHTNING_CFLAGS="$LIGHTNING_CFLAGS -DDISASSEMBLER=1"	;;
+	*)								;;
+    esac
 fi
 
 cpu=
@@ -61,7 +64,7 @@ case "$target_cpu" in
     i?86|x86_64)	cpu=x86		;;
     *arm*)		cpu=arm		;;
     *mips*)		cpu=mips	;;
-    *ppc*)		cpu=ppc		;;
+    *powerpc*)		cpu=ppc		;;
     *)					;;
 esac
 if test x$cpu = x; then
diff --git a/include/lightning/jit_ppc.h b/include/lightning/jit_ppc.h
index 52111c8f0..d42b8cc55 100644
--- a/include/lightning/jit_ppc.h
+++ b/include/lightning/jit_ppc.h
@@ -29,7 +29,7 @@ typedef enum {
 #define jit_r(i)		(_R11 + (i))
 #define jit_r_num()		3
 #define jit_v(i)		(_R30 - (i))
-#define jit_r_num()		17
+#define jit_v_num()		17
 #define jit_arg_f_reg_p(i)	((i) >= 0 && (i) < 8)
 #define jit_f(i)		(_F0 + (i))
 #define jit_f_num()		6
diff --git a/include/lightning/jit_private.h b/include/lightning/jit_private.h
index d2db6c236..6107ffa78 100644
--- a/include/lightning/jit_private.h
+++ b/include/lightning/jit_private.h
@@ -369,8 +369,8 @@ _emit_ldxi_d(jit_state_t*, jit_int32_t, jit_int32_t, jit_word_t);
 extern void
 _emit_stxi_d(jit_state_t*, jit_word_t, jit_int32_t, jit_int32_t);
 
-extern void jit_init_debug();
-extern void jit_finish_debug();
+extern void jit_init_debug(void);
+extern void jit_finish_debug(void);
 
 /*
  * Externs
diff --git a/lib/jit_ppc-cpu.c b/lib/jit_ppc-cpu.c
index 4cfa5614d..729d27528 100644
--- a/lib/jit_ppc-cpu.c
+++ b/lib/jit_ppc-cpu.c
@@ -16,10 +16,7 @@
  */
 
 #if PROTO
-/* quite a lot of space for fixed computation of possible stack arguments
- * this currently is done mostly to keep it simple, as the vm has only
- * one function */
-#  define stack_framesize		224
+#  define stack_framesize		80
 #  define ii(i)				*_jit->pc.ui++ = i
 #  define can_sign_extend_short_p(im)	((im) >= -32768 && (im) <= 32767)
 #  define can_zero_extend_short_p(im)	((im) >= 0 && (im) <= 65535)
@@ -2209,46 +2206,37 @@ _calli_p(jit_state_t *_jit, jit_word_t i0)
 static void
 _prolog(jit_state_t *_jit, jit_node_t *node)
 {
-    unsigned long	 regno;
+    unsigned long	regno;
 
-    subi(_SP_REGNO, _SP_REGNO, stack_framesize);
     /* return address */
     MFLR(_R0_REGNO);
-    stxi(0, _SP_REGNO, _R0_REGNO);
 
-    /* save any clobbered  callee save fpr register */
-    /* FIXME actually, no "clean" interface to use these registers */
-    for (regno = _F31; regno >= _F14; regno--) {
-	if (jit_regset_tstbit(_jit->function->regset, regno))
-	    stxi_d(stack_framesize - rn(regno) * 8, _SP_REGNO, regno);
-    }
     /* save any clobbered callee save gpr register */
     regno = jit_regset_scan1(_jit->function->regset, _R14);
     if (regno == ULONG_MAX || regno > _R31)
 	regno = _R31;	/* aka _FP_REGNO */
-    STMW(regno, _SP_REGNO, rn(regno) * 4 + 8);
-    movr(_FP_REGNO, _SP_REGNO);
-    /* alloca and/or space for excess parameters */
-    subi(_SP_REGNO, _SP_REGNO, _jit->function->stack);
+    STMW(rn(regno), _SP_REGNO, -(32 * 4) + rn(regno) * 4);
+
+    stxi(8, _SP_REGNO, _R0_REGNO);
+    STWU(_SP_REGNO, _SP_REGNO, -(stack_framesize + _jit->function->stack + 16));
+    addi(_FP_REGNO, _SP_REGNO, _jit->function->stack + 16);
 }
 
 static void
 _epilog(jit_state_t *_jit, jit_node_t *node)
 {
-    unsigned long	 regno;
+    unsigned long	regno;
+
+    //ldxi(_SP_REGNO, _SP_REGNO, 0);
+    LWZ(_SP_REGNO, _SP_REGNO, 0);
+    ldxi(_R0_REGNO, _SP_REGNO, 8);
+
+    MTLR(_R0_REGNO);
 
-    movr(_SP_REGNO, _FP_REGNO);
-    for (regno = _F31; regno >= _F14; regno--) {
-	if (jit_regset_tstbit(_jit->function->regset, regno))
-	    ldxi_d(regno, _SP_REGNO, stack_framesize - rn(regno) * 8);
-    }
     regno = jit_regset_scan1(_jit->function->regset, _R14);
     if (regno == ULONG_MAX || regno > _R31)
 	regno = _R31;	/* aka _FP_REGNO */
-    LMW(rn(regno), _SP_REGNO, regno * 4 + 8);
-    ldxi(_R0_REGNO, _SP_REGNO, 0);
-    addi(_SP_REGNO, _SP_REGNO, stack_framesize);
-    MTLR(_R0_REGNO);
+    LMW(rn(regno), _SP_REGNO, -(32 * 4) + rn(regno) * 4);
     BLR();
 }
 
diff --git a/lib/lightning.c b/lib/lightning.c
index 69abeeb78..7bef394e1 100644
--- a/lib/lightning.c
+++ b/lib/lightning.c
@@ -1221,8 +1221,10 @@ _jit_setup(jit_state_t *_jit, jit_block_t *block)
 		    jit_regset_setbit(reglive, node->u.w);
 		}
 	    case jit_code_calli:
-		for (value = jit_regset_scan1(regmask, 0); value != ULONG_MAX;
-		     value = jit_regset_scan1(regmask, value + 1)) {
+		for (value = 0; value < _jit->reglen; ++value) {
+		    value = jit_regset_scan1(regmask, value);
+		    if (value >= _jit->reglen)
+			break;
 		    spec = jit_class(_rvs[value].spec);
 		    if (!(spec & jit_class_sav))
 			jit_regset_clrbit(regmask, value);
@@ -1349,8 +1351,10 @@ _jit_update(jit_state_t *_jit, jit_bool_t setup, jit_node_t *node,
 		    jit_regset_clrbit(*mask, JIT_FRET);
 		}
 #endif
-		for (value = jit_regset_scan1(*mask, 0); value != ULONG_MAX;
-		     value = jit_regset_scan1(*mask, value + 1)) {
+		for (value = 0; value < _jit->reglen; ++value) {
+		    value = jit_regset_scan1(*mask, value);
+		    if (value >= _jit->reglen)
+			break;
 		    spec = jit_class(_rvs[value].spec);
 		    if (!(spec & jit_class_sav))
 			jit_regset_clrbit(*mask, value);