Re: comment error about OP_VARARG in lopcodes.h

[KHMan <keinhong@...>]

VirusCamp wrote:
> I'm working on luadec, but got confused about OP_VARARG in lua-5.1.4.
> I think the comment is wrong, that should be R(A), R(A+1), ...,
> R(A+B-2) = vararg
>
> lopcodes.h line 210
> OP_VARARG/*	A B	R(A), R(A+1), ..., R(A+B-1) = vararg		*/
>
>
> lvm.c line 751
>       case OP_VARARG: {
>         int b = GETARG_B(i) - 1;
> ..........
>         for (j = 0; j < b; j++) {

Nothing wrong there. You can plug in some numbers in order to 
'see' the indices and ranges better.

GETARG_B(i)'s zero value is taken by multiple return mode, since b 
is -1 when GETARG_B(i) == 0 and -1 is LUA_MULTRET in the test.

When GETARG_B(i) is 1, b = 0 and the loop iterates once only, for 
one value. So, A+B-1 = A+1-1 = A.

I think perhaps you have confused b with B in the comments. B is 
GETARG_B(i).

--
Cheers,
Kein-Hong Man (esq.)
Kuala Lumpur, Malaysia