Details

Comments and small improvements in the manual.

1 files changed, 17 insertions, 4 deletions

diff --git a/lopcodes.h b/lopcodes.h
index d6a47e5a..7c274515 100644
--- a/lopcodes.h
+++ b/lopcodes.h
@@ -190,7 +190,8 @@ enum OpMode {iABC, iABx, iAsBx, iAx, isJ};  /* basic instruction formats */
 
 
 /*
-** grep "ORDER OP" if you change these enums
+** Grep "ORDER OP" if you change these enums. Opcodes marked with a (*)
+** has extra descriptions in the notes after the enumeration.
 */
 
 typedef enum {
@@ -203,7 +204,7 @@ OP_LOADF,/*	A sBx	R[A] := (lua_Number)sBx				*/
 OP_LOADK,/*     A Bx    R[A] := K[Bx]                                   */
 OP_LOADKX,/*    A       R[A] := K[extra arg]                            */
 OP_LOADFALSE,/* A       R[A] := false                                   */
-OP_LFALSESKIP,/*A       R[A] := false; pc++                             */
+OP_LFALSESKIP,/*A       R[A] := false; pc++     (*)                     */
 OP_LOADTRUE,/*  A       R[A] := true                                    */
 OP_LOADNIL,/*   A B     R[A], R[A+1], ..., R[A+B] := nil                */
 OP_GETUPVAL,/*  A B     R[A] := UpValue[B]                              */
@@ -254,7 +255,7 @@ OP_BXOR,/*	A B C	R[A] := R[B] ~ R[C]				*/
 OP_SHL,/*       A B C   R[A] := R[B] << R[C]                            */
 OP_SHR,/*       A B C   R[A] := R[B] >> R[C]                            */
 
-OP_MMBIN,/*     A B C   call C metamethod over R[A] and R[B]            */
+OP_MMBIN,/*     A B C   call C metamethod over R[A] and R[B]    (*)     */
 OP_MMBINI,/*    A sB C k        call C metamethod over R[A] and sB      */
 OP_MMBINK,/*    A B C k         call C metamethod over R[A] and K[B]    */
 
@@ -280,7 +281,7 @@ OP_GTI,/*	A sB k	if ((R[A] > sB) ~= k) then pc++			*/
 OP_GEI,/*       A sB k  if ((R[A] >= sB) ~= k) then pc++                */
 
 OP_TEST,/*      A k     if (not R[A] == k) then pc++                    */
-OP_TESTSET,/*   A B k   if (not R[B] == k) then pc++ else R[A] := R[B]  */
+OP_TESTSET,/*   A B k   if (not R[B] == k) then pc++ else R[A] := R[B] (*) */
 
 OP_CALL,/*      A B C   R[A], ... ,R[A+C-2] := R[A](R[A+1], ... ,R[A+B-1]) */
 OP_TAILCALL,/*  A B C k return R[A](R[A+1], ... ,R[A+B-1])              */
@@ -315,6 +316,18 @@ OP_EXTRAARG/*	Ax	extra (larger) argument for previous opcode	*/
 
 /*===========================================================================
   Notes:
+
+  (*) Opcode OP_LFALSESKIP is used to convert a condition to a boolean
+  value, in a code equivalent to (not cond ? false : true).  (It
+  produces false and skips the next instruction producing true.)
+
+  (*) Opcodes OP_MMBIN and variants follow each arithmetic and
+  bitwise opcode. If the operation succeeds, it skips this next
+  opcode. Otherwise, this opcode calls the corresponding metamethod.
+
+  (*) Opcode OP_TESTSET is used in short-circuit expressions that need
+  both to jump and to produce a value, such as (a = b or c).
+
   (*) In OP_CALL, if (B == 0) then B = top - A. If (C == 0), then
   'top' is set to last_result+1, so next open instruction (OP_CALL,
   OP_RETURN*, OP_SETLIST) may use 'top'.