diff --git a/libs/gamecode/opcodes.py b/libs/gamecode/opcodes.py
index ac5aa5e51..d6cb80f6f 100644
--- a/libs/gamecode/opcodes.py
+++ b/libs/gamecode/opcodes.py
@@ -5,6 +5,9 @@ bitmap_txt = """
 0 0011 mmss pop
 0 1ccc ttss compare
 0 0000 00nn
+0 0000 0000 noop
+0 0000 0001 adjstk
+0 0000 0010 constant
 0 1011 nnnn
 0 1111 nnnn
 
@@ -75,6 +78,14 @@ etype_tt = ["ev_int", "ev_float", "ev_long", "ev_double"]
 unsigned_t = ["ev_uint", "ev_ulong"]
 float_t = ["ev_float", "ev_double"]
 
+adjstk_formats = {
+    "opcode": "OP_ADJSTK",
+    "mnemonic": "adjstk",
+    "opname": "adjstk",
+    "format": "%sa, %sb",
+    "widths": "0, 0, 0",
+    "types": "ev_short, ev_short, ev_invalid",
+}
 bitops_formats = {
     "opcode": "OP_{op_bit[oo].upper()}_{bit_type[t]}_{ss+1}",
     "mnemonic": "{op_bit[oo]}",
@@ -157,6 +168,14 @@ compare2_formats = {
         "cmp_types": unsigned_t,
     },
 }
+constant_formats = {
+    "opcode": "OP_LDCONST",
+    "mnemonic": "ldconst",
+    "opname": "ldconst",
+    "format": "%sa, %sb, %gc",
+    "widths": "0, 0, -1",
+    "types": "ev_short, ev_short, ev_void",
+}
 convert_formats = {
     "opcode": "OP_CONV",
     "mnemonic": "conv",
@@ -268,6 +287,14 @@ move_formats = {
         ],
     },
 }
+noop_formats = {
+    "opcode": "OP_NOP",
+    "mnemonic": "nop",
+    "opname": "nop",
+    "format": "there were plums...",
+    "widths": "0, 0, 0",
+    "types": "ev_invalid, ev_invalid, ev_invalid",
+}
 push_formats = {
     "opcode": "OP_PUSH_{op_mode[mm]}_{ss+1}",
     "mnemonic": "push",
@@ -473,11 +500,13 @@ with_formats = {
 }
 
 group_map = {
+    "adjstk":   adjstk_formats,
     "bitops":   bitops_formats,
     "branch":   branch_formats,
     "call":     call_formats,
     "compare":  compare_formats,
     "compare2": compare2_formats,
+    "constant": constant_formats,
     "convert":  convert_formats,
     "hops":     hops_formats,
     "jump":     jump_formats,
@@ -486,6 +515,7 @@ group_map = {
     "mathops":  mathops_formats,
     "memset":   memset_formats,
     "move":     move_formats,
+    "noop":     noop_formats,
     "push":     push_formats,
     "pushregs": pushregs_formats,
     "pop":      pop_formats,
diff --git a/libs/gamecode/pr_exec.c b/libs/gamecode/pr_exec.c
index 15885244c..a7581cbc4 100644
--- a/libs/gamecode/pr_exec.c
+++ b/libs/gamecode/pr_exec.c
@@ -2766,6 +2766,18 @@ pr_exec_ruamoko (progs_t *pr, int exitdepth)
 		pr_opcode_e st_op = st->op & OP_MASK;
 		switch (st_op) {
 			// 0 0000
+			case OP_NOP:
+				break;
+			case OP_ADJSTK:
+				if (st->a || (st->b & 3)) {
+					PR_RunError (pr, "invalid stack adjustment: %d, %d",
+								 st->a, (short) st->b);
+				}
+				*pr->globals.stack += (short) st->b;
+				break;
+			case OP_LDCONST:
+				PR_RunError (pr, "OP_LDCONST not implemented");
+				break;
 			case OP_LOAD_B_1:
 			case OP_LOAD_C_1:
 			case OP_LOAD_D_1: