From: divverent <divverent@d7cf8633-e32d-0410-b094-e92efae38249>
Date: Tue, 7 Jan 2014 19:22:59 +0000 (+0000)
Subject: Use an explicit jump table for QCVM instruction dispatch.
X-Git-Tag: xonotic-v0.8.1~29^2~114
X-Git-Url: https://git.rm.cloudns.org/?a=commitdiff_plain;h=91efd4d4260983eae86f644ff1813cc391d3c27e;p=xonotic%2Fdarkplaces.git

Use an explicit jump table for QCVM instruction dispatch.

Also, duplicate the dispatch into the end of each case for additional
speedup (each of these branches gets a separate branch prediction slot
on many CPUs, which pays off quickly).

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@12044 d7cf8633-e32d-0410-b094-e92efae38249
---

diff --git a/prvm_exec.c b/prvm_exec.c
index b926f26c..65ee31b2 100644
--- a/prvm_exec.c
+++ b/prvm_exec.c
@@ -716,6 +716,9 @@ static void PRVM_StatementCoverageEvent(prvm_prog_t *prog, mfunction_t *func, in
 	Con_Printf("prvm_coverage: %s just executed a statement at %s for the first time. Coverage: %.2f%%.\n", prog->name, PRVM_WhereAmI(vabuf, sizeof(vabuf), prog, func, statement), prog->statements_covered * 100.0 / prog->numstatements);
 }
 
+#ifdef __GNUC__
+#define HAVE_COMPUTED_GOTOS 1
+#endif
 
 #define OPA ((prvm_eval_t *)&prog->globals.fp[st->operand[0]])
 #define OPB ((prvm_eval_t *)&prog->globals.fp[st->operand[1]])
diff --git a/prvm_execprogram.h b/prvm_execprogram.h
index d7182fc7..5e94073d 100644
--- a/prvm_execprogram.h
+++ b/prvm_execprogram.h
@@ -12,6 +12,100 @@
 
 // This code isn't #ifdef/#define protectable, don't try.
 
+#if HAVE_COMPUTED_GOTOS && !(PRVMSLOWINTERPRETER || PRVMTIMEPROFILING)
+  // NOTE: Due to otherwise duplicate labels, only ONE interpreter path may
+  // ever hit this!
+# define USE_COMPUTED_GOTOS 1
+#endif
+
+#if USE_COMPUTED_GOTOS
+  // Must exactly match opcode_e enum in pr_comp.h
+    const static void *dispatchtable[] = {
+	&&handle_OP_DONE,
+	&&handle_OP_MUL_F,
+	&&handle_OP_MUL_V,
+	&&handle_OP_MUL_FV,
+	&&handle_OP_MUL_VF,
+	&&handle_OP_DIV_F,
+	&&handle_OP_ADD_F,
+	&&handle_OP_ADD_V,
+	&&handle_OP_SUB_F,
+	&&handle_OP_SUB_V,
+
+	&&handle_OP_EQ_F,
+	&&handle_OP_EQ_V,
+	&&handle_OP_EQ_S,
+	&&handle_OP_EQ_E,
+	&&handle_OP_EQ_FNC,
+
+	&&handle_OP_NE_F,
+	&&handle_OP_NE_V,
+	&&handle_OP_NE_S,
+	&&handle_OP_NE_E,
+	&&handle_OP_NE_FNC,
+
+	&&handle_OP_LE,
+	&&handle_OP_GE,
+	&&handle_OP_LT,
+	&&handle_OP_GT,
+
+	&&handle_OP_LOAD_F,
+	&&handle_OP_LOAD_V,
+	&&handle_OP_LOAD_S,
+	&&handle_OP_LOAD_ENT,
+	&&handle_OP_LOAD_FLD,
+	&&handle_OP_LOAD_FNC,
+
+	&&handle_OP_ADDRESS,
+
+	&&handle_OP_STORE_F,
+	&&handle_OP_STORE_V,
+	&&handle_OP_STORE_S,
+	&&handle_OP_STORE_ENT,
+	&&handle_OP_STORE_FLD,
+	&&handle_OP_STORE_FNC,
+
+	&&handle_OP_STOREP_F,
+	&&handle_OP_STOREP_V,
+	&&handle_OP_STOREP_S,
+	&&handle_OP_STOREP_ENT,
+	&&handle_OP_STOREP_FLD,
+	&&handle_OP_STOREP_FNC,
+
+	&&handle_OP_RETURN,
+	&&handle_OP_NOT_F,
+	&&handle_OP_NOT_V,
+	&&handle_OP_NOT_S,
+	&&handle_OP_NOT_ENT,
+	&&handle_OP_NOT_FNC,
+	&&handle_OP_IF,
+	&&handle_OP_IFNOT,
+	&&handle_OP_CALL0,
+	&&handle_OP_CALL1,
+	&&handle_OP_CALL2,
+	&&handle_OP_CALL3,
+	&&handle_OP_CALL4,
+	&&handle_OP_CALL5,
+	&&handle_OP_CALL6,
+	&&handle_OP_CALL7,
+	&&handle_OP_CALL8,
+	&&handle_OP_STATE,
+	&&handle_OP_GOTO,
+	&&handle_OP_AND,
+	&&handle_OP_OR,
+
+	&&handle_OP_BITAND,
+	&&handle_OP_BITOR
+	    };
+#define DISPATCH_OPCODE() \
+    goto *dispatchtable[(++st)->op]
+#define HANDLE_OPCODE(opcode) handle_##opcode
+
+    DISPATCH_OPCODE(); // jump to first opcode
+#else // USE_COMPUTED_GOTOS
+#define DISPATCH_OPCODE() break
+#define HANDLE_OPCODE(opcode) case opcode
+
 #if PRVMSLOWINTERPRETER
 		{
 			if (prog->watch_global_type != ev_void)
@@ -32,6 +126,9 @@
 		while (1)
 		{
 			st++;
+#endif // USE_COMPUTED_GOTOS
+
+#if !USE_COMPUTED_GOTOS
 
 #if PRVMSLOWINTERPRETER
 			if (prog->trace)
@@ -45,44 +142,44 @@
 					PRVM_Breakpoint(prog, prog->break_stack_index, "Breakpoint hit");
 				}
 #endif
-
 			switch (st->op)
 			{
-			case OP_ADD_F:
+#endif
+			HANDLE_OPCODE(OP_ADD_F):
 				OPC->_float = OPA->_float + OPB->_float;
-				break;
-			case OP_ADD_V:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_ADD_V):
 				OPC->vector[0] = OPA->vector[0] + OPB->vector[0];
 				OPC->vector[1] = OPA->vector[1] + OPB->vector[1];
 				OPC->vector[2] = OPA->vector[2] + OPB->vector[2];
-				break;
-			case OP_SUB_F:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_SUB_F):
 				OPC->_float = OPA->_float - OPB->_float;
-				break;
-			case OP_SUB_V:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_SUB_V):
 				OPC->vector[0] = OPA->vector[0] - OPB->vector[0];
 				OPC->vector[1] = OPA->vector[1] - OPB->vector[1];
 				OPC->vector[2] = OPA->vector[2] - OPB->vector[2];
-				break;
-			case OP_MUL_F:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_MUL_F):
 				OPC->_float = OPA->_float * OPB->_float;
-				break;
-			case OP_MUL_V:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_MUL_V):
 				OPC->_float = OPA->vector[0]*OPB->vector[0] + OPA->vector[1]*OPB->vector[1] + OPA->vector[2]*OPB->vector[2];
-				break;
-			case OP_MUL_FV:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_MUL_FV):
 				tempfloat = OPA->_float;
 				OPC->vector[0] = tempfloat * OPB->vector[0];
 				OPC->vector[1] = tempfloat * OPB->vector[1];
 				OPC->vector[2] = tempfloat * OPB->vector[2];
-				break;
-			case OP_MUL_VF:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_MUL_VF):
 				tempfloat = OPB->_float;
 				OPC->vector[0] = tempfloat * OPA->vector[0];
 				OPC->vector[1] = tempfloat * OPA->vector[1];
 				OPC->vector[2] = tempfloat * OPA->vector[2];
-				break;
-			case OP_DIV_F:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_DIV_F):
 				if( OPB->_float != 0.0f )
 				{
 					OPC->_float = OPA->_float / OPB->_float;
@@ -98,96 +195,96 @@
 					}
 					OPC->_float = 0.0f;
 				}
-				break;
-			case OP_BITAND:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_BITAND):
 				OPC->_float = (prvm_int_t)OPA->_float & (prvm_int_t)OPB->_float;
-				break;
-			case OP_BITOR:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_BITOR):
 				OPC->_float = (prvm_int_t)OPA->_float | (prvm_int_t)OPB->_float;
-				break;
-			case OP_GE:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_GE):
 				OPC->_float = OPA->_float >= OPB->_float;
-				break;
-			case OP_LE:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_LE):
 				OPC->_float = OPA->_float <= OPB->_float;
-				break;
-			case OP_GT:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_GT):
 				OPC->_float = OPA->_float > OPB->_float;
-				break;
-			case OP_LT:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_LT):
 				OPC->_float = OPA->_float < OPB->_float;
-				break;
-			case OP_AND:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_AND):
 				OPC->_float = FLOAT_IS_TRUE_FOR_INT(OPA->_int) && FLOAT_IS_TRUE_FOR_INT(OPB->_int); // TODO change this back to float, and add AND_I to be used by fteqcc for anything not a float
-				break;
-			case OP_OR:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_OR):
 				OPC->_float = FLOAT_IS_TRUE_FOR_INT(OPA->_int) || FLOAT_IS_TRUE_FOR_INT(OPB->_int); // TODO change this back to float, and add OR_I to be used by fteqcc for anything not a float
-				break;
-			case OP_NOT_F:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_NOT_F):
 				OPC->_float = !FLOAT_IS_TRUE_FOR_INT(OPA->_int);
-				break;
-			case OP_NOT_V:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_NOT_V):
 				OPC->_float = !OPA->vector[0] && !OPA->vector[1] && !OPA->vector[2];
-				break;
-			case OP_NOT_S:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_NOT_S):
 				OPC->_float = !OPA->string || !*PRVM_GetString(prog, OPA->string);
-				break;
-			case OP_NOT_FNC:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_NOT_FNC):
 				OPC->_float = !OPA->function;
-				break;
-			case OP_NOT_ENT:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_NOT_ENT):
 				OPC->_float = (OPA->edict == 0);
-				break;
-			case OP_EQ_F:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_EQ_F):
 				OPC->_float = OPA->_float == OPB->_float;
-				break;
-			case OP_EQ_V:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_EQ_V):
 				OPC->_float = (OPA->vector[0] == OPB->vector[0]) && (OPA->vector[1] == OPB->vector[1]) && (OPA->vector[2] == OPB->vector[2]);
-				break;
-			case OP_EQ_S:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_EQ_S):
 				OPC->_float = !strcmp(PRVM_GetString(prog, OPA->string),PRVM_GetString(prog, OPB->string));
-				break;
-			case OP_EQ_E:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_EQ_E):
 				OPC->_float = OPA->_int == OPB->_int;
-				break;
-			case OP_EQ_FNC:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_EQ_FNC):
 				OPC->_float = OPA->function == OPB->function;
-				break;
-			case OP_NE_F:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_NE_F):
 				OPC->_float = OPA->_float != OPB->_float;
-				break;
-			case OP_NE_V:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_NE_V):
 				OPC->_float = (OPA->vector[0] != OPB->vector[0]) || (OPA->vector[1] != OPB->vector[1]) || (OPA->vector[2] != OPB->vector[2]);
-				break;
-			case OP_NE_S:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_NE_S):
 				OPC->_float = strcmp(PRVM_GetString(prog, OPA->string),PRVM_GetString(prog, OPB->string));
-				break;
-			case OP_NE_E:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_NE_E):
 				OPC->_float = OPA->_int != OPB->_int;
-				break;
-			case OP_NE_FNC:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_NE_FNC):
 				OPC->_float = OPA->function != OPB->function;
-				break;
+				DISPATCH_OPCODE();
 
 		//==================
-			case OP_STORE_F:
-			case OP_STORE_ENT:
-			case OP_STORE_FLD:		// integers
-			case OP_STORE_S:
-			case OP_STORE_FNC:		// pointers
+			HANDLE_OPCODE(OP_STORE_F):
+			HANDLE_OPCODE(OP_STORE_ENT):
+			HANDLE_OPCODE(OP_STORE_FLD):		// integers
+			HANDLE_OPCODE(OP_STORE_S):
+			HANDLE_OPCODE(OP_STORE_FNC):		// pointers
 				OPB->_int = OPA->_int;
-				break;
-			case OP_STORE_V:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_STORE_V):
 				OPB->ivector[0] = OPA->ivector[0];
 				OPB->ivector[1] = OPA->ivector[1];
 				OPB->ivector[2] = OPA->ivector[2];
-				break;
+				DISPATCH_OPCODE();
 
-			case OP_STOREP_F:
-			case OP_STOREP_ENT:
-			case OP_STOREP_FLD:		// integers
-			case OP_STOREP_S:
-			case OP_STOREP_FNC:		// pointers
+			HANDLE_OPCODE(OP_STOREP_F):
+			HANDLE_OPCODE(OP_STOREP_ENT):
+			HANDLE_OPCODE(OP_STOREP_FLD):		// integers
+			HANDLE_OPCODE(OP_STOREP_S):
+			HANDLE_OPCODE(OP_STOREP_FNC):		// pointers
 				if ((prvm_uint_t)OPB->_int - cached_entityfields >= cached_entityfieldsarea_entityfields)
 				{
 					if ((prvm_uint_t)OPB->_int >= cached_entityfieldsarea)
@@ -204,8 +301,8 @@
 				}
 				ptr = (prvm_eval_t *)(cached_edictsfields + OPB->_int);
 				ptr->_int = OPA->_int;
-				break;
-			case OP_STOREP_V:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_STOREP_V):
 				if ((prvm_uint_t)OPB->_int - cached_entityfields > (prvm_uint_t)cached_entityfieldsarea_entityfields_3)
 				{
 					if ((prvm_uint_t)OPB->_int > cached_entityfieldsarea_3)
@@ -224,9 +321,9 @@
 				ptr->ivector[0] = OPA->ivector[0];
 				ptr->ivector[1] = OPA->ivector[1];
 				ptr->ivector[2] = OPA->ivector[2];
-				break;
+				DISPATCH_OPCODE();
 
-			case OP_ADDRESS:
+			HANDLE_OPCODE(OP_ADDRESS):
 				if ((prvm_uint_t)OPA->edict >= cached_max_edicts)
 				{
 					PreError();
@@ -248,13 +345,13 @@
 				}
 #endif
 				OPC->_int = OPA->edict * cached_entityfields + OPB->_int;
-				break;
+				DISPATCH_OPCODE();
 
-			case OP_LOAD_F:
-			case OP_LOAD_FLD:
-			case OP_LOAD_ENT:
-			case OP_LOAD_S:
-			case OP_LOAD_FNC:
+			HANDLE_OPCODE(OP_LOAD_F):
+			HANDLE_OPCODE(OP_LOAD_FLD):
+			HANDLE_OPCODE(OP_LOAD_ENT):
+			HANDLE_OPCODE(OP_LOAD_S):
+			HANDLE_OPCODE(OP_LOAD_FNC):
 				if ((prvm_uint_t)OPA->edict >= cached_max_edicts)
 				{
 					PreError();
@@ -269,9 +366,9 @@
 				}
 				ed = PRVM_PROG_TO_EDICT(OPA->edict);
 				OPC->_int = ((prvm_eval_t *)(ed->fields.ip + OPB->_int))->_int;
-				break;
+				DISPATCH_OPCODE();
 
-			case OP_LOAD_V:
+			HANDLE_OPCODE(OP_LOAD_V):
 				if ((prvm_uint_t)OPA->edict >= cached_max_edicts)
 				{
 					PreError();
@@ -289,11 +386,11 @@
 				OPC->ivector[0] = ptr->ivector[0];
 				OPC->ivector[1] = ptr->ivector[1];
 				OPC->ivector[2] = ptr->ivector[2];
-				break;
+				DISPATCH_OPCODE();
 
 		//==================
 
-			case OP_IFNOT:
+			HANDLE_OPCODE(OP_IFNOT):
 				if(!FLOAT_IS_TRUE_FOR_INT(OPA->_int))
 				// TODO add an "int-if", and change this one to OPA->_float
 				// although mostly unneeded, thanks to the only float being false being 0x0 and 0x80000000 (negative zero)
@@ -310,9 +407,9 @@
 						prog->error_cmd("%s runaway loop counter hit limit of %d jumps\ntip: read above for list of most-executed functions", prog->name, jumpcount);
 					}
 				}
-				break;
+				DISPATCH_OPCODE();
 
-			case OP_IF:
+			HANDLE_OPCODE(OP_IF):
 				if(FLOAT_IS_TRUE_FOR_INT(OPA->_int))
 				// TODO add an "int-if", and change this one, as well as the FLOAT_IS_TRUE_FOR_INT usages, to OPA->_float
 				// although mostly unneeded, thanks to the only float being false being 0x0 and 0x80000000 (negative zero)
@@ -329,9 +426,9 @@
 						prog->error_cmd("%s runaway loop counter hit limit of %d jumps\ntip: read above for list of most-executed functions", prog->name, jumpcount);
 					}
 				}
-				break;
+				DISPATCH_OPCODE();
 
-			case OP_GOTO:
+			HANDLE_OPCODE(OP_GOTO):
 				prog->xfunction->profile += (st - startst);
 				st = cached_statements + st->jumpabsolute - 1;	// offset the st++
 				startst = st;
@@ -342,17 +439,17 @@
 					PRVM_Profile(prog, 1<<30, 0.01, 0);
 					prog->error_cmd("%s runaway loop counter hit limit of %d jumps\ntip: read above for list of most-executed functions", prog->name, jumpcount);
 				}
-				break;
-
-			case OP_CALL0:
-			case OP_CALL1:
-			case OP_CALL2:
-			case OP_CALL3:
-			case OP_CALL4:
-			case OP_CALL5:
-			case OP_CALL6:
-			case OP_CALL7:
-			case OP_CALL8:
+				DISPATCH_OPCODE();
+
+			HANDLE_OPCODE(OP_CALL0):
+			HANDLE_OPCODE(OP_CALL1):
+			HANDLE_OPCODE(OP_CALL2):
+			HANDLE_OPCODE(OP_CALL3):
+			HANDLE_OPCODE(OP_CALL4):
+			HANDLE_OPCODE(OP_CALL5):
+			HANDLE_OPCODE(OP_CALL6):
+			HANDLE_OPCODE(OP_CALL7):
+			HANDLE_OPCODE(OP_CALL8):
 #ifdef PRVMTIMEPROFILING 
 				tm = Sys_DirtyTime();
 				prog->xfunction->tprofile += (tm - starttm >= 0 && tm - starttm < 1800) ? (tm - starttm) : 0;
@@ -413,10 +510,10 @@
 				else
 					st = cached_statements + PRVM_EnterFunction(prog, newf);
 				startst = st;
-				break;
+				DISPATCH_OPCODE();
 
-			case OP_DONE:
-			case OP_RETURN:
+			HANDLE_OPCODE(OP_DONE):
+			HANDLE_OPCODE(OP_RETURN):
 #ifdef PRVMTIMEPROFILING 
 				tm = Sys_DirtyTime();
 				prog->xfunction->tprofile += (tm - starttm >= 0 && tm - starttm < 1800) ? (tm - starttm) : 0;
@@ -433,9 +530,9 @@
 				startst = st;
 				if (prog->depth <= exitdepth)
 					goto cleanup; // all done
-				break;
+				DISPATCH_OPCODE();
 
-			case OP_STATE:
+			HANDLE_OPCODE(OP_STATE):
 				if(cached_flag & PRVM_OP_STATE)
 				{
 					ed = PRVM_PROG_TO_EDICT(PRVM_gameglobaledict(self));
@@ -449,162 +546,162 @@
 					prog->xstatement = st - cached_statements;
 					prog->error_cmd("OP_STATE not supported by %s", prog->name);
 				}
-				break;
+				DISPATCH_OPCODE();
 
 // LordHavoc: to be enabled when Progs version 7 (or whatever it will be numbered) is finalized
 /*
-			case OP_ADD_I:
+			HANDLE_OPCODE(OP_ADD_I):
 				OPC->_int = OPA->_int + OPB->_int;
-				break;
-			case OP_ADD_IF:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_ADD_IF):
 				OPC->_int = OPA->_int + (prvm_int_t) OPB->_float;
-				break;
-			case OP_ADD_FI:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_ADD_FI):
 				OPC->_float = OPA->_float + (prvm_vec_t) OPB->_int;
-				break;
-			case OP_SUB_I:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_SUB_I):
 				OPC->_int = OPA->_int - OPB->_int;
-				break;
-			case OP_SUB_IF:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_SUB_IF):
 				OPC->_int = OPA->_int - (prvm_int_t) OPB->_float;
-				break;
-			case OP_SUB_FI:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_SUB_FI):
 				OPC->_float = OPA->_float - (prvm_vec_t) OPB->_int;
-				break;
-			case OP_MUL_I:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_MUL_I):
 				OPC->_int = OPA->_int * OPB->_int;
-				break;
-			case OP_MUL_IF:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_MUL_IF):
 				OPC->_int = OPA->_int * (prvm_int_t) OPB->_float;
-				break;
-			case OP_MUL_FI:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_MUL_FI):
 				OPC->_float = OPA->_float * (prvm_vec_t) OPB->_int;
-				break;
-			case OP_MUL_VI:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_MUL_VI):
 				OPC->vector[0] = (prvm_vec_t) OPB->_int * OPA->vector[0];
 				OPC->vector[1] = (prvm_vec_t) OPB->_int * OPA->vector[1];
 				OPC->vector[2] = (prvm_vec_t) OPB->_int * OPA->vector[2];
-				break;
-			case OP_DIV_VF:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_DIV_VF):
 				{
 					float temp = 1.0f / OPB->_float;
 					OPC->vector[0] = temp * OPA->vector[0];
 					OPC->vector[1] = temp * OPA->vector[1];
 					OPC->vector[2] = temp * OPA->vector[2];
 				}
-				break;
-			case OP_DIV_I:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_DIV_I):
 				OPC->_int = OPA->_int / OPB->_int;
-				break;
-			case OP_DIV_IF:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_DIV_IF):
 				OPC->_int = OPA->_int / (prvm_int_t) OPB->_float;
-				break;
-			case OP_DIV_FI:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_DIV_FI):
 				OPC->_float = OPA->_float / (prvm_vec_t) OPB->_int;
-				break;
-			case OP_CONV_IF:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_CONV_IF):
 				OPC->_float = OPA->_int;
-				break;
-			case OP_CONV_FI:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_CONV_FI):
 				OPC->_int = OPA->_float;
-				break;
-			case OP_BITAND_I:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_BITAND_I):
 				OPC->_int = OPA->_int & OPB->_int;
-				break;
-			case OP_BITOR_I:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_BITOR_I):
 				OPC->_int = OPA->_int | OPB->_int;
-				break;
-			case OP_BITAND_IF:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_BITAND_IF):
 				OPC->_int = OPA->_int & (prvm_int_t)OPB->_float;
-				break;
-			case OP_BITOR_IF:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_BITOR_IF):
 				OPC->_int = OPA->_int | (prvm_int_t)OPB->_float;
-				break;
-			case OP_BITAND_FI:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_BITAND_FI):
 				OPC->_float = (prvm_int_t)OPA->_float & OPB->_int;
-				break;
-			case OP_BITOR_FI:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_BITOR_FI):
 				OPC->_float = (prvm_int_t)OPA->_float | OPB->_int;
-				break;
-			case OP_GE_I:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_GE_I):
 				OPC->_float = OPA->_int >= OPB->_int;
-				break;
-			case OP_LE_I:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_LE_I):
 				OPC->_float = OPA->_int <= OPB->_int;
-				break;
-			case OP_GT_I:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_GT_I):
 				OPC->_float = OPA->_int > OPB->_int;
-				break;
-			case OP_LT_I:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_LT_I):
 				OPC->_float = OPA->_int < OPB->_int;
-				break;
-			case OP_AND_I:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_AND_I):
 				OPC->_float = OPA->_int && OPB->_int;
-				break;
-			case OP_OR_I:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_OR_I):
 				OPC->_float = OPA->_int || OPB->_int;
-				break;
-			case OP_GE_IF:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_GE_IF):
 				OPC->_float = (prvm_vec_t)OPA->_int >= OPB->_float;
-				break;
-			case OP_LE_IF:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_LE_IF):
 				OPC->_float = (prvm_vec_t)OPA->_int <= OPB->_float;
-				break;
-			case OP_GT_IF:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_GT_IF):
 				OPC->_float = (prvm_vec_t)OPA->_int > OPB->_float;
-				break;
-			case OP_LT_IF:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_LT_IF):
 				OPC->_float = (prvm_vec_t)OPA->_int < OPB->_float;
-				break;
-			case OP_AND_IF:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_AND_IF):
 				OPC->_float = (prvm_vec_t)OPA->_int && OPB->_float;
-				break;
-			case OP_OR_IF:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_OR_IF):
 				OPC->_float = (prvm_vec_t)OPA->_int || OPB->_float;
-				break;
-			case OP_GE_FI:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_GE_FI):
 				OPC->_float = OPA->_float >= (prvm_vec_t)OPB->_int;
-				break;
-			case OP_LE_FI:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_LE_FI):
 				OPC->_float = OPA->_float <= (prvm_vec_t)OPB->_int;
-				break;
-			case OP_GT_FI:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_GT_FI):
 				OPC->_float = OPA->_float > (prvm_vec_t)OPB->_int;
-				break;
-			case OP_LT_FI:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_LT_FI):
 				OPC->_float = OPA->_float < (prvm_vec_t)OPB->_int;
-				break;
-			case OP_AND_FI:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_AND_FI):
 				OPC->_float = OPA->_float && (prvm_vec_t)OPB->_int;
-				break;
-			case OP_OR_FI:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_OR_FI):
 				OPC->_float = OPA->_float || (prvm_vec_t)OPB->_int;
-				break;
-			case OP_NOT_I:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_NOT_I):
 				OPC->_float = !OPA->_int;
-				break;
-			case OP_EQ_I:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_EQ_I):
 				OPC->_float = OPA->_int == OPB->_int;
-				break;
-			case OP_EQ_IF:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_EQ_IF):
 				OPC->_float = (prvm_vec_t)OPA->_int == OPB->_float;
-				break;
-			case OP_EQ_FI:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_EQ_FI):
 				OPC->_float = OPA->_float == (prvm_vec_t)OPB->_int;
-				break;
-			case OP_NE_I:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_NE_I):
 				OPC->_float = OPA->_int != OPB->_int;
-				break;
-			case OP_NE_IF:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_NE_IF):
 				OPC->_float = (prvm_vec_t)OPA->_int != OPB->_float;
-				break;
-			case OP_NE_FI:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_NE_FI):
 				OPC->_float = OPA->_float != (prvm_vec_t)OPB->_int;
-				break;
-			case OP_STORE_I:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_STORE_I):
 				OPB->_int = OPA->_int;
-				break;
-			case OP_STOREP_I:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_STOREP_I):
 #if PRBOUNDSCHECK
 				if (OPB->_int < 0 || OPB->_int + 4 > pr_edictareasize)
 				{
@@ -615,8 +712,8 @@
 #endif
 				ptr = (prvm_eval_t *)(prog->edictsfields + OPB->_int);
 				ptr->_int = OPA->_int;
-				break;
-			case OP_LOAD_I:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_LOAD_I):
 #if PRBOUNDSCHECK
 				if (OPA->edict < 0 || OPA->edict >= prog->max_edicts)
 				{
@@ -633,14 +730,14 @@
 #endif
 				ed = PRVM_PROG_TO_EDICT(OPA->edict);
 				OPC->_int = ((prvm_eval_t *)((int *)ed->v + OPB->_int))->_int;
-				break;
-
-			case OP_GSTOREP_I:
-			case OP_GSTOREP_F:
-			case OP_GSTOREP_ENT:
-			case OP_GSTOREP_FLD:		// integers
-			case OP_GSTOREP_S:
-			case OP_GSTOREP_FNC:		// pointers
+				DISPATCH_OPCODE();
+
+			HANDLE_OPCODE(OP_GSTOREP_I):
+			HANDLE_OPCODE(OP_GSTOREP_F):
+			HANDLE_OPCODE(OP_GSTOREP_ENT):
+			HANDLE_OPCODE(OP_GSTOREP_FLD):		// integers
+			HANDLE_OPCODE(OP_GSTOREP_S):
+			HANDLE_OPCODE(OP_GSTOREP_FNC):		// pointers
 #if PRBOUNDSCHECK
 				if (OPB->_int < 0 || OPB->_int >= pr_globaldefs)
 				{
@@ -650,8 +747,8 @@
 				}
 #endif
 				pr_iglobals[OPB->_int] = OPA->_int;
-				break;
-			case OP_GSTOREP_V:
+				DISPATCH_OPCODE();
+			HANDLE_OPCODE(OP_GSTOREP_V):
 #if PRBOUNDSCHECK
 				if (OPB->_int < 0 || OPB->_int + 2 >= pr_globaldefs)
 				{
@@ -663,9 +760,9 @@
 				pr_iglobals[OPB->_int  ] = OPA->ivector[0];
 				pr_iglobals[OPB->_int+1] = OPA->ivector[1];
 				pr_iglobals[OPB->_int+2] = OPA->ivector[2];
-				break;
+				DISPATCH_OPCODE();
 
-			case OP_GADDRESS:
+			HANDLE_OPCODE(OP_GADDRESS):
 				i = OPA->_int + (prvm_int_t) OPB->_float;
 #if PRBOUNDSCHECK
 				if (i < 0 || i >= pr_globaldefs)
@@ -676,14 +773,14 @@
 				}
 #endif
 				OPC->_int = pr_iglobals[i];
-				break;
-
-			case OP_GLOAD_I:
-			case OP_GLOAD_F:
-			case OP_GLOAD_FLD:
-			case OP_GLOAD_ENT:
-			case OP_GLOAD_S:
-			case OP_GLOAD_FNC:
+				DISPATCH_OPCODE();
+
+			HANDLE_OPCODE(OP_GLOAD_I):
+			HANDLE_OPCODE(OP_GLOAD_F):
+			HANDLE_OPCODE(OP_GLOAD_FLD):
+			HANDLE_OPCODE(OP_GLOAD_ENT):
+			HANDLE_OPCODE(OP_GLOAD_S):
+			HANDLE_OPCODE(OP_GLOAD_FNC):
 #if PRBOUNDSCHECK
 				if (OPA->_int < 0 || OPA->_int >= pr_globaldefs)
 				{
@@ -693,9 +790,9 @@
 				}
 #endif
 				OPC->_int = pr_iglobals[OPA->_int];
-				break;
+				DISPATCH_OPCODE();
 
-			case OP_GLOAD_V:
+			HANDLE_OPCODE(OP_GLOAD_V):
 #if PRBOUNDSCHECK
 				if (OPA->_int < 0 || OPA->_int + 2 >= pr_globaldefs)
 				{
@@ -707,19 +804,20 @@
 				OPC->ivector[0] = pr_iglobals[OPA->_int  ];
 				OPC->ivector[1] = pr_iglobals[OPA->_int+1];
 				OPC->ivector[2] = pr_iglobals[OPA->_int+2];
-				break;
+				DISPATCH_OPCODE();
 
-			case OP_BOUNDCHECK:
+			HANDLE_OPCODE(OP_BOUNDCHECK):
 				if (OPA->_int < 0 || OPA->_int >= st->b)
 				{
 					PreError();
 					prog->error_cmd("%s Progs boundcheck failed at line number %d, value is < 0 or >= %d", prog->name, st->b, st->c);
 					goto cleanup;
 				}
-				break;
+				DISPATCH_OPCODE();
 
 */
 
+#if !USE_COMPUTED_GOTOS
 			default:
 				PreError();
 				prog->error_cmd("Bad opcode %i in %s", st->op, prog->name);
@@ -742,5 +840,11 @@
 			}
 #endif
 		}
+#endif // !USE_COMPUTED_GOTOS
+
+#undef DISPATCH_OPCODE
+#undef HANDLE_OPCODE
+#undef USE_COMPUTED_GOTOS
+
 
 #undef PreError