diff --git a/src/eval/eval_interpret.c b/src/eval/eval_interpret.c
index ca4db434..c7c824a4 100644
--- a/src/eval/eval_interpret.c
+++ b/src/eval/eval_interpret.c
@@ -67,14 +67,14 @@ e_interpret(String8 bytecode)
   {
     // rjf: consume next opcode
     RDI_EvalOp op = (RDI_EvalOp)*ptr;
-    U8 ctrlbits = 0;
+    U16 ctrlbits = 0;
     if(op < RDI_EvalOp_COUNT)
     {
       ctrlbits = rdi_eval_op_ctrlbits_table[op];
     }
     else switch(op)
     {
-      case E_IRExtKind_SetSpace:{ctrlbits = RDI_EVAL_CTRLBITS(16, 0, 0);}break;
+      case E_IRExtKind_SetSpace:{ctrlbits = RDI_EVAL_CTRLBITS(32, 0, 0);}break;
       default:
       {
         result.code = E_InterpretationCode_BadOp;
diff --git a/src/eval/eval_ir.c b/src/eval/eval_ir.c
index 428c2ea4..92c81386 100644
--- a/src/eval/eval_ir.c
+++ b/src/eval/eval_ir.c
@@ -78,7 +78,7 @@ e_select_ir_ctx(E_IRCtx *ctx)
 internal void
 e_oplist_push_op(Arena *arena, E_OpList *list, RDI_EvalOp opcode, E_Value value)
 {
-  U8 ctrlbits = rdi_eval_op_ctrlbits_table[opcode];
+  U16 ctrlbits = rdi_eval_op_ctrlbits_table[opcode];
   U32 p_size = RDI_DECODEN_FROM_CTRLBITS(ctrlbits);
   E_Op *node = push_array_no_zero(arena, E_Op, 1);
   node->opcode = opcode;
@@ -149,7 +149,7 @@ internal void
 e_oplist_push_string_literal(Arena *arena, E_OpList *list, String8 string)
 {
   RDI_EvalOp opcode = RDI_EvalOp_ConstString;
-  U8 ctrlbits = rdi_eval_op_ctrlbits_table[opcode];
+  U16 ctrlbits = rdi_eval_op_ctrlbits_table[opcode];
   U32 p_size = RDI_DECODEN_FROM_CTRLBITS(ctrlbits);
   E_Op *node = push_array_no_zero(arena, E_Op, 1);
   node->opcode = opcode;
@@ -1383,7 +1383,7 @@ e_append_oplist_from_irtree(Arena *arena, E_IRNode *root, E_OpList *out)
       else
       {
         // rjf: append ops for all children
-        U8 ctrlbits = rdi_eval_op_ctrlbits_table[op];
+        U16 ctrlbits = rdi_eval_op_ctrlbits_table[op];
         U64 child_count = RDI_POPN_FROM_CTRLBITS(ctrlbits);
         U64 idx = 0;
         for(E_IRNode *child = root->first;
@@ -1428,7 +1428,7 @@ e_bytecode_from_oplist(Arena *arena, E_OpList *oplist)
       default:
       {
         // rjf: compute bytecode advance
-        U8 ctrlbits = rdi_eval_op_ctrlbits_table[opcode];
+        U16 ctrlbits = rdi_eval_op_ctrlbits_table[opcode];
         U64 extra_byte_count = RDI_DECODEN_FROM_CTRLBITS(ctrlbits);
         U8 *next_ptr = ptr + 1 + extra_byte_count;
         Assert(next_ptr <= opl);
diff --git a/src/eval/eval_parse.c b/src/eval/eval_parse.c
index 59fc8faf..f6d5ff48 100644
--- a/src/eval/eval_parse.c
+++ b/src/eval/eval_parse.c
@@ -1385,7 +1385,7 @@ e_parse_expr_from_text_tokens__prec(Arena *arena, String8 text, E_TokenArray *to
                         {
                           break;
                         }
-                        U8 ctrlbits = rdi_eval_op_ctrlbits_table[op];
+                        U16 ctrlbits = rdi_eval_op_ctrlbits_table[op];
                         U32 p_size = RDI_DECODEN_FROM_CTRLBITS(ctrlbits);
                         bytecode_size += 1+p_size;
                       }
diff --git a/src/lib_rdi_format/rdi_format.c b/src/lib_rdi_format/rdi_format.c
index e4f20e25..4e79ae5e 100644
--- a/src/lib_rdi_format/rdi_format.c
+++ b/src/lib_rdi_format/rdi_format.c
@@ -92,7 +92,7 @@ RDI_U8 rdi_section_is_required_table[37] =
 0,
 };
 
-RDI_U8 rdi_eval_op_ctrlbits_table[49] =
+RDI_U16 rdi_eval_op_ctrlbits_table[49] =
 {
 RDI_EVAL_CTRLBITS(0, 0, 0),
 RDI_EVAL_CTRLBITS(0, 0, 0),
diff --git a/src/lib_rdi_format/rdi_format.h b/src/lib_rdi_format/rdi_format.h
index ede67a4d..bbf04e99 100644
--- a/src/lib_rdi_format/rdi_format.h
+++ b/src/lib_rdi_format/rdi_format.h
@@ -997,10 +997,10 @@ typedef RDI_U32_Table RDI_U32_NameMapBuckets;
 typedef RDI_U32_Table RDI_U32_NameMapNodes;
 #endif
 
-#define RDI_EVAL_CTRLBITS(decodeN,popN,pushN) ((decodeN) | ((popN) << 5) | ((pushN) << 7))
-#define RDI_DECODEN_FROM_CTRLBITS(ctrlbits)   ((ctrlbits) & 0x1f)
-#define RDI_POPN_FROM_CTRLBITS(ctrlbits)      (((ctrlbits) >> 5) & 0x3)
-#define RDI_PUSHN_FROM_CTRLBITS(ctrlbits)     (((ctrlbits) >> 7) & 0x1)
+#define RDI_EVAL_CTRLBITS(decodeN,popN,pushN) (((decodeN) << 8) | ((popN) << 4) | ((pushN) << 0))
+#define RDI_DECODEN_FROM_CTRLBITS(ctrlbits)   (((ctrlbits) >> 8) & 0xff)
+#define RDI_POPN_FROM_CTRLBITS(ctrlbits)      (((ctrlbits) >> 4) & 0xf)
+#define RDI_PUSHN_FROM_CTRLBITS(ctrlbits)     (((ctrlbits) >> 0) & 0xf)
 #define RDI_EncodeRegReadParam(reg,bytesize,bytepos) ((reg)|((bytesize)<<8)|((bytepos)<<16))
 
 typedef struct RDI_Header RDI_Header;
@@ -1361,6 +1361,6 @@ RDI_PROC RDI_U8 *rdi_explanation_string_from_eval_conversion_kind(RDI_EvalConver
 
 extern RDI_U16 rdi_section_element_size_table[37];
 extern RDI_U8 rdi_section_is_required_table[37];
-extern RDI_U8 rdi_eval_op_ctrlbits_table[49];
+extern RDI_U16 rdi_eval_op_ctrlbits_table[49];
 
 #endif // RDI_FORMAT_H
diff --git a/src/lib_rdi_make/rdi_make.c b/src/lib_rdi_make/rdi_make.c
index a04fa1c1..0fb28271 100644
--- a/src/lib_rdi_make/rdi_make.c
+++ b/src/lib_rdi_make/rdi_make.c
@@ -970,7 +970,7 @@ rdim_scope_push_local(RDIM_Arena *arena, RDIM_ScopeChunkList *scopes, RDIM_Scope
 RDI_PROC void
 rdim_bytecode_push_op(RDIM_Arena *arena, RDIM_EvalBytecode *bytecode, RDI_EvalOp op, RDI_U64 p)
 {
-  RDI_U8 ctrlbits = rdi_eval_op_ctrlbits_table[op];
+  RDI_U16 ctrlbits = rdi_eval_op_ctrlbits_table[op];
   RDI_U32 p_size = RDI_DECODEN_FROM_CTRLBITS(ctrlbits);
   
   RDIM_EvalBytecodeOp *node = rdim_push_array(arena, RDIM_EvalBytecodeOp, 1);
diff --git a/src/rdi_format/rdi_format.mdesk b/src/rdi_format/rdi_format.mdesk
index f62d7bf0..c615ec78 100644
--- a/src/rdi_format/rdi_format.mdesk
+++ b/src/rdi_format/rdi_format.mdesk
@@ -1337,14 +1337,14 @@ RDI_EvalConversionKindTable:
 
 @gen(enums)
 ```
-#define RDI_EVAL_CTRLBITS(decodeN,popN,pushN) ((decodeN) | ((popN) << 5) | ((pushN) << 7))
-#define RDI_DECODEN_FROM_CTRLBITS(ctrlbits)   ((ctrlbits) & 0x1f)
-#define RDI_POPN_FROM_CTRLBITS(ctrlbits)      (((ctrlbits) >> 5) & 0x3)
-#define RDI_PUSHN_FROM_CTRLBITS(ctrlbits)     (((ctrlbits) >> 7) & 0x1)
+#define RDI_EVAL_CTRLBITS(decodeN,popN,pushN) (((decodeN) << 8) | ((popN) << 4) | ((pushN) << 0))
+#define RDI_DECODEN_FROM_CTRLBITS(ctrlbits)   (((ctrlbits) >> 8) & 0xff)
+#define RDI_POPN_FROM_CTRLBITS(ctrlbits)      (((ctrlbits) >> 4) & 0xf)
+#define RDI_PUSHN_FROM_CTRLBITS(ctrlbits)     (((ctrlbits) >> 0) & 0xf)
 #define RDI_EncodeRegReadParam(reg,bytesize,bytepos) ((reg)|((bytesize)<<8)|((bytepos)<<16))
 ```
 
-@data(RDI_U8) rdi_eval_op_ctrlbits_table:
+@data(RDI_U16) rdi_eval_op_ctrlbits_table:
 {
   @expand(RDI_EvalOpTable a) `RDI_EVAL_CTRLBITS($(a.num_decodes), $(a.num_pops), $(a.num_pushes))`;
 }