diff --git a/library/compiler/ppc/fixnum.factor b/library/compiler/ppc/fixnum.factor
index b9d3a8c85c..b73fd719c6 100644
--- a/library/compiler/ppc/fixnum.factor
+++ b/library/compiler/ppc/fixnum.factor
@@ -38,7 +38,8 @@ M: %fixnum- generate-node ( vop -- )
     \ ADD \ SUBF simple-overflow ;
 
 M: %fixnum* generate-node ( vop -- )
-    dup >3-vop< dup dup tag-bits SRAWI
+    #! Note that this assumes the output will be in r3.
+    >3-vop< dup dup tag-bits SRAWI
     0 MTXER
     [ >r >r drop 4 r> r> MULLWO. 3 ] 2keep
     <label> "end" set
@@ -51,8 +52,7 @@ M: %fixnum* generate-node ( vop -- )
     "s48_bignum_arithmetic_shift" f compile-c-call
     ! An untagged pointer to the bignum is now in r3; tag it
     3 4 bignum-tag ORI
-    "end" get save-xt
-    vop-out-1 v>operand 4 MR ;
+    "end" get save-xt ;
 
 M: %fixnum/i generate-node ( vop -- )
     dup >3-vop< swap DIVW
@@ -62,9 +62,9 @@ M: %fixnum/i generate-node ( vop -- )
     #! The same code is used for %fixnum/i and %fixnum/mod.
     #! mdest is vreg where to put the modulus. Note this has
     #! precise vreg requirements.
-    20 17 18 DIVW  ! divide in2 by in1, store result in out1
-    21 20 18 MULLW ! multiply out1 by in1, store result in in1
-    19 21 17 SUBF  ! subtract in2 from in1, store result in out1.
+    6 3 4 DIVW  ! divide in2 by in1, store result in out1
+    7 6 4 MULLW ! multiply out1 by in1, store result in in1
+    5 8 3 SUBF  ! subtract in2 from in1, store result in out1.
     ;
 
 M: %fixnum-mod generate-node ( vop -- )
@@ -74,8 +74,8 @@ M: %fixnum-mod generate-node ( vop -- )
 M: %fixnum/mod generate-node ( vop -- )
     #! This has specific vreg requirements.
     drop generate-fixnum/mod
-    17 20 MR
-    17 17 tag-fixnum ;
+    3 6 MR
+    3 3 tag-fixnum ;
 
 M: %fixnum-bitand generate-node ( vop -- )
     >3-vop< AND ;
@@ -119,9 +119,6 @@ M: %fixnum>> generate-node ( vop -- )
 M: %fixnum-sgn generate-node ( vop -- )
     dest/src dupd 31 SRAWI dup untag ;
 
-: MULLW 0 0 (MULLW) ;
-: MULLW. 0 1 (MULLW) ;
-
 : compare ( vop -- )
     dup vop-in-2 v>operand swap vop-in-1 dup integer? [
         0 -rot address CMPI
diff --git a/library/compiler/ppc/generator.factor b/library/compiler/ppc/generator.factor
index 08c3b149e5..9e28074339 100644
--- a/library/compiler/ppc/generator.factor
+++ b/library/compiler/ppc/generator.factor
@@ -12,8 +12,6 @@ kernel-internals lists math memory namespaces words ;
 : compile-c-call ( symbol dll -- )
     2dup dlsym  19 LOAD32  0 1 rel-dlsym  19 MTLR  BLRL ;
 
-M: vreg v>operand vreg-n 17 + ;
-
 M: %prologue generate-node ( vop -- )
     drop
     1 1 -16 STWU
@@ -39,18 +37,19 @@ M: %call-label generate-node ( vop -- )
     B ;
 
 : word-addr ( word -- )
-    dup word-xt 19 LOAD32  0 1 rel-word ;
+    #! Load a word address into r3.
+    dup word-xt 3 LOAD32  0 1 rel-word ;
 
 : compile-call ( label -- )
     #! Far C call for primitives, near C call for compiled defs.
-    dup primitive? [ word-addr  19 MTLR  BLRL ] [ BL ] ifte ;
+    dup primitive? [ word-addr  3 MTLR  BLRL ] [ BL ] ifte ;
 
 M: %call generate-node ( vop -- )
     vop-label dup postpone-word compile-call ;
 
 : compile-jump ( label -- )
     #! For tail calls. IP not saved on C stack.
-    dup primitive? [ word-addr  19 MTCTR  BCTR ] [ B ] ifte ;
+    dup primitive? [ word-addr  3 MTCTR  BCTR ] [ B ] ifte ;
 
 M: %jump generate-node ( vop -- )
     vop-label dup postpone-word  compile-epilogue compile-jump ;
@@ -68,9 +67,9 @@ M: %jump-t generate-node ( vop -- )
     conditional BNE ;
 
 M: %return-to generate-node ( vop -- )
-    vop-label 0 18 LOAD32  absolute-16/16
+    vop-label 0 3 LOAD32  absolute-16/16
     1 1 -16 STWU
-    18 1 20 STW ;
+    3 1 20 STW ;
 
 M: %return generate-node ( vop -- )
     drop compile-epilogue BLR ;
@@ -91,13 +90,13 @@ M: %retag-fixnum generate-node ( vop -- )
 
 M: %dispatch generate-node ( vop -- )
     0 <vreg> check-src
-    17 17 2 SLWI
+    3 3 2 SLWI
     ! The value 24 is a magic number. It is the length of the
     ! instruction sequence that follows to be generated.
-    0 1 rel-address  compiled-offset 24 + 18 LOAD32
-    17 17 18 ADD
-    17 17 0 LWZ
-    17 MTLR
+    0 1 rel-address  compiled-offset 24 + 4 LOAD32
+    3 3 4 ADD
+    3 3 0 LWZ
+    3 MTLR
     BLR ;
 
 M: %type generate-node ( vop -- )
@@ -105,24 +104,24 @@ M: %type generate-node ( vop -- )
     <label> "f" set
     <label> "end" set
     ! Get the tag
-    17 18 tag-mask ANDI
+    3 4 tag-mask ANDI
     ! Compare with object tag number (3).
-    0 18 object-tag CMPI
+    0 4 object-tag CMPI
     ! Jump if the object doesn't store type info in its header
     "end" get BNE
     ! It does store type info in its header
     ! Is the pointer itself equal to 3? Then its F_TYPE (9).
-    0 17 object-tag CMPI
+    0 3 object-tag CMPI
     "f" get BEQ
     ! The pointer is not equal to 3. Load the object header.
-    18 17 object-tag neg LWZ
-    18 18 3 SRAWI
+    4 3 object-tag neg LWZ
+    4 4 3 SRAWI
     "end" get B
     "f" get save-xt
     ! The pointer is equal to 3. Load F_TYPE (9).
-    f type 18 LI
+    f type 4 LI
     "end" get save-xt
-    17 18 MR ;
+    3 4 MR ;
 
 M: %tag generate-node ( vop -- )
     dup vop-in-1 v>operand swap vop-out-1 v>operand tag-mask ANDI ;
diff --git a/library/compiler/ppc/slots.factor b/library/compiler/ppc/slots.factor
index 5fd051c91f..4f5e2c20e0 100644
--- a/library/compiler/ppc/slots.factor
+++ b/library/compiler/ppc/slots.factor
@@ -32,12 +32,13 @@ M: %fast-set-slot generate-node ( vop -- )
 
 M: %write-barrier generate-node ( vop -- )
     #! Mark the card pointed to by vreg.
+    #! Uses r6 for storage.
     vop-in-1 v>operand
     dup dup card-bits SRAWI
     dup dup 16 ADD
-    20 over 0 LBZ
-    20 20 card-mark ORI
-    20 swap 0 STB ;
+    6 over 0 LBZ
+    6 6 card-mark ORI
+    6 swap 0 STB ;
 
 : userenv ( reg -- )
     #! Load the userenv pointer in a virtual register.