diff --git a/mach/powerpc/libem/ior.s b/mach/powerpc/libem/ior.s
index 61e099934..b3ebf81e9 100644
--- a/mach/powerpc/libem/ior.s
+++ b/mach/powerpc/libem/ior.s
@@ -3,11 +3,13 @@
 .sect .text
 
 ! Set union.
-!  Stack: ( b a -- a+b )
-!  With r3 = size of set
+!  Stack: ( size b a -- a+b )
 
 .define .ior
 .ior:
+	lwz r3, 0 (sp)
+	addi sp, sp, 4
+
 	mr	r4, sp			! r4 = ptr to set a
 	add	r5, sp, r3		! r5 = ptr to set b
 	rlwinm	r6, r3, 30, 2, 31
diff --git a/mach/powerpc/libem/rck.s b/mach/powerpc/libem/rck.s
new file mode 100644
index 000000000..b716e5091
--- /dev/null
+++ b/mach/powerpc/libem/rck.s
@@ -0,0 +1,22 @@
+#include "powerpc.h"
+
+.sect .text
+
+! Bounds check. Traps if the value is out of range.
+!  Stack: ( descriptor value -- )
+
+.define .rck
+.rck:
+    lwz r3, 0 (sp)
+    lwz r4, 4 (sp)
+    addi sp, sp, 8
+
+    lwz r5, 0 (r3)
+    cmp cr0, 0, r4, r5
+    bc IFTRUE, LT, .trap_erange
+
+    lwz r5, 4 (r3)
+    cmp cr0, 0, r4, r5
+    bc IFTRUE, GT, .trap_erange
+
+	bclr ALWAYS, 0, 0
diff --git a/mach/powerpc/libem/set.s b/mach/powerpc/libem/set.s
index 18ad877e8..daffb9c3d 100644
--- a/mach/powerpc/libem/set.s
+++ b/mach/powerpc/libem/set.s
@@ -3,11 +3,14 @@
 .sect .text
 
 ! Create singleton set.
-!  Stack: ( -- set )
-!  With r3 = size of set, r4 = bit number
+!  Stack: ( size bitnumber -- set )
 
 .define .set
 .set:
+	lwz     r3, 0 (sp)
+	lwz     r4, 4 (sp)
+	addi    sp, sp, 8
+
 	rlwinm	r7, r3, 30, 2, 31
 	neg	r5, r3
 	add	sp, sp, r5		! allocate set
diff --git a/mach/powerpc/libem/zer.s b/mach/powerpc/libem/zer.s
index ba978ba3e..697a5715f 100644
--- a/mach/powerpc/libem/zer.s
+++ b/mach/powerpc/libem/zer.s
@@ -3,11 +3,13 @@
 .sect .text
 
 ! Create empty set.
-!  Stack: ( -- set )
-!  With r3 = size of set
+!  Stack: ( size -- set )
 
 .define .zer
 .zer:
+	lwz     r3, 0(sp)
+	addi    sp, sp, 4
+
 	rlwinm	r7, r3, 30, 2, 31
 	addi	r4, r0, 0		! r4 = zero
 	neg	r5, r3
diff --git a/mach/powerpc/ncg/table b/mach/powerpc/ncg/table
index 52f335c3d..6498c591c 100644
--- a/mach/powerpc/ncg/table
+++ b/mach/powerpc/ncg/table
@@ -1503,18 +1503,14 @@ PATTERNS
 			yields {OR_RC, %2, lo(%1.val)}
 
 	pat ior defined($1)                /* OR set */
-		with STACK
-			kills ALL
-			gen
-				move {CONST, $1}, R3
-				bl {LABEL, ".ior"}
+		leaving
+			loc $1
+			cal ".ior"
 
 	/* OR set (variable), used in lang/m2/libm2/LtoUset.e */
 	pat ior !defined($1)
-		with GPR3 STACK
-			kills ALL
-			gen
-				bl {LABEL, ".ior"}
+		leaving
+			cal ".ior"
 
 	pat xor $1==4                      /* XOR word */
 		with REG REG
@@ -1572,12 +1568,10 @@ PATTERNS
 		leaving
 			loc 0
 
-	pat zer defined($1)	   	   /* Create empty set */
-		with STACK
-			kills ALL
-			gen
-				move {CONST, $1}, R3
-				bl {LABEL, ".zer"}
+	pat zer defined($1)	   	           /* Create empty set */
+		leaving
+			loc $1
+			cal ".zer"
 
 	pat sli $1==4                      /* Shift left (second << top) */
 		with CONST_ALL GPR
@@ -1655,27 +1649,19 @@ PATTERNS
 /* Sets */
 
 	pat set defined($1)                /* Create singleton set */
-		with GPR4 STACK
-			kills ALL
-			gen
-				move {CONST, $1}, R3
-				bl {LABEL, ".set"}
+		leaving
+			loc $1
+			cal ".set"
 
 	/* Create set (variable), used in lang/m2/libm2/LtoUset.e */
 	pat set !defined($1)
-		with GPR3 GPR4 STACK
-			kills ALL
-			gen
-				bl {LABEL, ".set"}
+		leaving
+			cal ".set"
 
 	pat inn defined($1)                /* Test for set bit */
-		with STACK
-			kills ALL
-			uses REG
-			gen
-				li32 %a, {CONST, $1}
-				stwu %a, {GPRINDIRECT, SP, 0-4}
-				bl {LABEL, ".inn"}
+		leaving
+			loc $1
+			cal ".inn"
 
 
 /* Boolean resolutions */
@@ -2066,6 +2052,16 @@ PATTERNS
 			loc $1
 			ass 4
 
+	pat lae rck $2==4                  /* Range check */
+		with GPR
+			uses CR0
+			gen
+				cmpli %a, {CONST, 0}, %1, {CONST, rom($1, 1)}
+				bc IFTRUE, LT, {LABEL, ".trap_erange"}
+				cmpli %a, {CONST, 0}, %1, {CONST, rom($1, 2)}
+				bc IFTRUE, GT, {LABEL, ".trap_erange"}
+
+
 
 
 /* Floating point support */
diff --git a/mach/proto/mcg/treebuilder.c b/mach/proto/mcg/treebuilder.c
index 667562e8d..ba4f7198f 100644
--- a/mach/proto/mcg/treebuilder.c
+++ b/mach/proto/mcg/treebuilder.c
@@ -66,7 +66,7 @@ static struct ir* pop(int size)
 
 #if 0
         /* If we try to pop something which is smaller than a word, convert it first. */
-        
+
         if (size < EM_wordsize)
             ir = convertu(ir, size);
 #endif
@@ -200,7 +200,7 @@ static struct ir* address_of_external(const char* label, arith offset)
 
 static struct ir* convert(struct ir* src, int srcsize, int destsize, int opcode)
 {
-    if (srcsize == 1) 
+    if (srcsize == 1)
     {
         if ((opcode == IR_FROMSI) || (opcode == IR_FROMSL))
         {
@@ -433,7 +433,7 @@ static void insn_simple(int opcode)
             );
             break;
         }
-            
+
         case op_cii: simple_convert(IR_FROMSI); break;
         case op_ciu: simple_convert(IR_FROMSI); break;
         case op_cui: simple_convert(IR_FROMUI); break;
@@ -528,10 +528,12 @@ static void insn_simple(int opcode)
         }
 
         /* FIXME: These instructions are really complex and barely used
-         * (Modula-2 bitset support, I believe). Leave them until later. */
+         * (Modula-2 and Pascal set support, I believe). Leave them until
+         * later. */
         case op_set: helper_function(".unimplemented_set"); break;
         case op_ior: helper_function(".unimplemented_ior"); break;
 
+
         case op_dch:
             push(
                 new_ir1(
@@ -540,7 +542,7 @@ static void insn_simple(int opcode)
                 )
             );
             break;
-            
+
         case op_lpb:
             push(
                 new_ir1(
@@ -607,29 +609,53 @@ static void insn_bvalue(int opcode, struct basicblock* leftbb, struct basicblock
     }
 }
 
-static void simple_alu1(int opcode, int size, int irop)
+static void simple_alu1(int opcode, int size, int irop, const char* fallback)
 {
-    struct ir* val = pop(size);
+    if (size > (2*EM_wordsize))
+    {
+        if (!fallback)
+            fatal("treebuilder: can't do opcode %d with size %d", opcode, size);
+        push(
+            new_wordir(size)
+        );
+        helper_function(fallback);
+    }
+    else
+    {
+        struct ir* val = pop(size);
 
-    push(
-        new_ir1(
-            irop, size,
-            val
-        )
-    );
+        push(
+            new_ir1(
+                irop, size,
+                val
+            )
+        );
+    }
 }
 
-static void simple_alu2(int opcode, int size, int irop)
+static void simple_alu2(int opcode, int size, int irop, const char* fallback)
 {
-    struct ir* right = pop(size);
-    struct ir* left = pop(size);
+    if (size > (2*EM_wordsize))
+    {
+        if (!fallback)
+            fatal("treebuilder: can't do opcode %d with size %d", opcode, size);
+        push(
+            new_wordir(size)
+        );
+        helper_function(fallback);
+    }
+    else
+    {
+        struct ir* right = pop(size);
+        struct ir* left = pop(size);
 
-    push(
-        new_ir2(
-            irop, size,
-            left, right
-        )
-    );
+        push(
+            new_ir2(
+                irop, size,
+                left, right
+            )
+        );
+    }
 }
 
 static struct ir* extract_block_refs(struct basicblock* bb)
@@ -708,39 +734,43 @@ static void insn_ivalue(int opcode, arith value)
 {
     switch (opcode)
     {
-        case op_adi: simple_alu2(opcode, value, IR_ADD); break;
-        case op_sbi: simple_alu2(opcode, value, IR_SUB); break;
-        case op_mli: simple_alu2(opcode, value, IR_MUL); break;
-        case op_dvi: simple_alu2(opcode, value, IR_DIV); break;
-        case op_rmi: simple_alu2(opcode, value, IR_MOD); break;
-        case op_sli: simple_alu2(opcode, value, IR_ASL); break;
-        case op_sri: simple_alu2(opcode, value, IR_ASR); break;
-        case op_ngi: simple_alu1(opcode, value, IR_NEG); break;
+        case op_adi: simple_alu2(opcode, value, IR_ADD, NULL); break;
+        case op_sbi: simple_alu2(opcode, value, IR_SUB, NULL); break;
+        case op_mli: simple_alu2(opcode, value, IR_MUL, NULL); break;
+        case op_dvi: simple_alu2(opcode, value, IR_DIV, NULL); break;
+        case op_rmi: simple_alu2(opcode, value, IR_MOD, NULL); break;
+        case op_sli: simple_alu2(opcode, value, IR_ASL, NULL); break;
+        case op_sri: simple_alu2(opcode, value, IR_ASR, NULL); break;
+        case op_ngi: simple_alu1(opcode, value, IR_NEG, NULL); break;
 
-        case op_adu: simple_alu2(opcode, value, IR_ADD); break;
-        case op_sbu: simple_alu2(opcode, value, IR_SUB); break;
-        case op_mlu: simple_alu2(opcode, value, IR_MUL); break;
-        case op_slu: simple_alu2(opcode, value, IR_LSL); break;
-        case op_sru: simple_alu2(opcode, value, IR_LSR); break;
-        case op_rmu: simple_alu2(opcode, value, IR_MODU); break;
-        case op_dvu: simple_alu2(opcode, value, IR_DIVU); break;
+        case op_adu: simple_alu2(opcode, value, IR_ADD, NULL); break;
+        case op_sbu: simple_alu2(opcode, value, IR_SUB, NULL); break;
+        case op_mlu: simple_alu2(opcode, value, IR_MUL, NULL); break;
+        case op_slu: simple_alu2(opcode, value, IR_LSL, NULL); break;
+        case op_sru: simple_alu2(opcode, value, IR_LSR, NULL); break;
+        case op_rmu: simple_alu2(opcode, value, IR_MODU, NULL); break;
+        case op_dvu: simple_alu2(opcode, value, IR_DIVU, NULL); break;
 
-        case op_and: simple_alu2(opcode, value, IR_AND); break;
-        case op_ior: simple_alu2(opcode, value, IR_OR); break;
-        case op_xor: simple_alu2(opcode, value, IR_EOR); break;
-        case op_com: simple_alu1(opcode, value, IR_NOT); break;
+        case op_and: simple_alu2(opcode, value, IR_AND, NULL); break;
+        case op_ior: simple_alu2(opcode, value, IR_OR, ".ior"); break;
+        case op_xor: simple_alu2(opcode, value, IR_EOR, NULL); break;
+        case op_com: simple_alu1(opcode, value, IR_NOT, NULL); break;
 
-        case op_adf: simple_alu2(opcode, value, IR_ADDF); break;
-        case op_sbf: simple_alu2(opcode, value, IR_SUBF); break;
-        case op_mlf: simple_alu2(opcode, value, IR_MULF); break;
-        case op_dvf: simple_alu2(opcode, value, IR_DIVF); break;
-        case op_ngf: simple_alu1(opcode, value, IR_NEGF); break;
+        case op_adf: simple_alu2(opcode, value, IR_ADDF, NULL); break;
+        case op_sbf: simple_alu2(opcode, value, IR_SUBF, NULL); break;
+        case op_mlf: simple_alu2(opcode, value, IR_MULF, NULL); break;
+        case op_dvf: simple_alu2(opcode, value, IR_DIVF, NULL); break;
+        case op_ngf: simple_alu1(opcode, value, IR_NEGF, NULL); break;
 
         case op_cmu: /* fall through */
         case op_cms: push(tristate_compare(value, IR_COMPAREUI)); break;
         case op_cmi: push(tristate_compare(value, IR_COMPARESI)); break;
         case op_cmf: push(tristate_compare(value, IR_COMPAREF)); break;
 
+        case op_rck: helper_function(".rck"); break;
+        case op_set: push(new_wordir(value)); helper_function(".set"); break;
+        case op_inn: push(new_wordir(value)); helper_function(".inn"); break;
+
         case op_lol:
             push(
                 load(
@@ -874,7 +904,7 @@ static void insn_ivalue(int opcode, arith value)
                 )
             );
             break;
-                
+
         case op_loc:
             push(
                 new_wordir(value)
@@ -1041,7 +1071,7 @@ static void insn_ivalue(int opcode, arith value)
             struct ir* right = pop(EM_pointersize);
             struct ir* left = pop(EM_pointersize);
 
-            struct ir* delta = 
+            struct ir* delta =
                 new_ir2(
                     IR_SUB, EM_pointersize,
                     left, right
@@ -1053,7 +1083,7 @@ static void insn_ivalue(int opcode, arith value)
             push(delta);
             break;
         }
-            
+
         case op_dup:
         {
             sequence_point();
@@ -1084,6 +1114,18 @@ static void insn_ivalue(int opcode, arith value)
             break;
         }
 
+        case op_zer:
+        {
+            if (value <= EM_wordsize)
+                push(new_constir(value, 0));
+            else
+            {
+                push(new_wordir(value));
+                helper_function(".zer");
+            }
+            break;
+        }
+
         case op_asp:
         {
             switch (value)
@@ -1108,15 +1150,12 @@ static void insn_ivalue(int opcode, arith value)
                         value -= s;
                     }
 
-                    if (value != 0)
-                    {
-                        appendir(
-                            new_ir1(
-                                IR_STACKADJUST, EM_pointersize,
-                                new_wordir(value)
-                            )
-                        );
-                    }
+                    appendir(
+                        new_ir1(
+                            IR_STACKADJUST, EM_pointersize,
+                            new_wordir(value)
+                        )
+                    );
                     break;
             }
             break;
@@ -1169,7 +1208,7 @@ static void insn_ivalue(int opcode, arith value)
             );
             break;
         }
-                    
+
         case op_lfr:
         {
             push(
@@ -1300,11 +1339,11 @@ static void insn_ivalue(int opcode, arith value)
                     new_labelir((value == 4) ? ".fef4" : ".fef8")
                 )
             );
-                    
+
             /* exit, leaving an int and then a float (or double) on the stack. */
             break;
         }
-            
+
         case op_fif:
         {
             /* fif is implemented by calling a helper function which then mutates
@@ -1320,11 +1359,11 @@ static void insn_ivalue(int opcode, arith value)
                     new_labelir((value == 4) ? ".fif4" : ".fif8")
                 )
             );
-                    
+
             /* exit, leaving two floats (or doubles) on the stack. */
             break;
         }
-            
+
         case op_lor:
         {
             switch (value)
@@ -1341,7 +1380,7 @@ static void insn_ivalue(int opcode, arith value)
                         )
                     );
                     break;
-                        
+
                 case 1:
                     push(
                         appendir(
@@ -1492,18 +1531,6 @@ static void insn_ivalue(int opcode, arith value)
             break;
         }
 
-        /* FIXME: These instructions are really complex and barely used
-         * (Modula-2 bitset support, I believe). Leave them until leter. */
-        case op_inn:
-        {
-            push(
-                new_wordir(value)
-            );
-
-            helper_function(".inn");
-            break;
-        }
-
         case op_lin:
         {
             /* Set line number --- ignore. */
@@ -1577,7 +1604,7 @@ static void insn_lvalue(int opcode, const char* label, arith offset)
                 )
             );
             break;
-                
+
         case op_ine:
             sequence_point();
             appendir(
@@ -1666,7 +1693,7 @@ static void insn_lvalue(int opcode, const char* label, arith offset)
             /* Set filename --- ignore. */
             break;
         }
-                    
+
         default:
             fatal("treebuilder: unknown lvalue instruction '%s'",
                 em_mnem[opcode - sp_fmnem]);
@@ -1699,7 +1726,7 @@ static void generate_tree(struct basicblock* bb)
                 break;
 
             case PARAM_LVALUE:
-                tracef('E', "label=%s offset=%d\n", 
+                tracef('E', "label=%s offset=%d\n",
                     em->u.lvalue.label, em->u.lvalue.offset);
                 insn_lvalue(em->opcode, em->u.lvalue.label, em->u.lvalue.offset);
                 break;
diff --git a/plat/linuxppc/libsys/trap.s b/plat/linuxppc/libsys/trap.s
index 09d3b0b21..296f17391 100644
--- a/plat/linuxppc/libsys/trap.s
+++ b/plat/linuxppc/libsys/trap.s
@@ -52,43 +52,48 @@ EUNIMPL = 63		! unimplemented em-instruction called
 .trap_ecase:
 	addi r3, r0, ECASE
 	b .trap
-	
+
 .define .trap_earray
 .trap_earray:
 	addi r3, r0, EARRAY
 	b .trap
-	
+
+.define .trap_erange
+.trap_erange:
+	addi r3, r0, ERANGE
+	b .trap
+
 .define .trap
 .trap:
 	cmpi cr0, 0, r3, 15      ! traps >15 can't be ignored
 	bc IFTRUE, LT, 1f
-	
+
 	addi r4, r0, 1
 	rlwnm r4, r4, r3, 0, 31  ! calculate trap bit
 	li32 r5, .ignmask
 	lwz r5, 0(r5)            ! load ignore mask
 	and. r4, r4, r5          ! compare
 	bclr IFFALSE, EQ, 0      ! return if non-zero
-	
+
 1:
 	li32 r4, .trppc
 	lwz r5, 0(r4)            ! load user trap routine
 	or. r5, r5, r5           ! test
 	bc IFTRUE, EQ, fatal     ! if no user trap routine, bail out
-	
+
 	addi r0, r0, 0
 	stw r0, 0(r4)            ! reset trap routine
-	
+
 	mfspr r0, lr
 	stwu r0, -4(sp)          ! save old lr
-	
+
 	stwu r3, -4(sp)
 	mtspr ctr, r5
 	bcctrl ALWAYS, 0, 0      ! call trap routine
-	
+
 	lwz r0, 4(sp)            ! load old lr again
 	addi sp, sp, 8           ! retract over stack usage
-	bclr ALWAYS, 0, 0        ! return 
+	bclr ALWAYS, 0, 0        ! return
 
 fatal:
 	addi r3, r0, 1
@@ -96,7 +101,7 @@ fatal:
 	addi r5, r0, 6
 	addi r0, r0, 4           ! write()
 	sc 0
-	
+
 	addi r0, r0, 1           ! exit()
 	sc 0
 
diff --git a/plat/qemuppc/libsys/trap.s b/plat/qemuppc/libsys/trap.s
index f05b907d0..280adc33b 100644
--- a/plat/qemuppc/libsys/trap.s
+++ b/plat/qemuppc/libsys/trap.s
@@ -49,11 +49,15 @@ EUNIMPL = 63		! unimplemented em-instruction called
 .define .trap_ecase
 .trap_ecase:
 	b .trp
-	
+
 .define .trap_earray
 .trap_earray:
 	b .trp
 
+.define .trap_erange
+.trap_erange:
+	b .trap
+
 .define .trp
 .define .trap
 .trp:
@@ -66,4 +70,3 @@ EUNIMPL = 63		! unimplemented em-instruction called
 	li32 r4, .trppc
 	stw r3, 0(r4)
 	bclr ALWAYS, 0, 0		! return
-	
\ No newline at end of file
diff --git a/tests/plat/charsignedness_p.p b/tests/plat/charsignedness_p.p
new file mode 100644
index 000000000..6263111ce
--- /dev/null
+++ b/tests/plat/charsignedness_p.p
@@ -0,0 +1,28 @@
+#
+(*$U+ -- enables underscores in identifiers *)
+
+program markrelease;
+
+type
+    charset = set of char;
+
+var
+    s : charset;
+    i : integer;
+
+procedure finished;
+    extern;
+
+procedure fail(line: integer);
+    extern;
+
+#define ASSERT(cond) \
+    if (not (cond)) then fail(__LINE__)
+
+begin
+    s := [];
+    for i := 0 to 255 do
+        s := s + [chr(i)];
+
+    finished
+end.
diff --git a/tests/plat/newdispose_p.p b/tests/plat/newdispose_p.p
index 36f09e99b..aa3be5a46 100644
--- a/tests/plat/newdispose_p.p
+++ b/tests/plat/newdispose_p.p
@@ -9,13 +9,13 @@ type
 var
     ptr1 : iptr;
     ptr2 : iptr;
-    
+
 procedure finished;
     extern;
 
 procedure fail(line: integer);
     extern;
-    
+
 #define ASSERT(cond) \
     if (not (cond)) then fail(__LINE__)