Re: LOADF vs LOADK
[
Date Prev][
Date Next][
Thread Prev][
Thread Next]
[
Date Index]
[
Thread Index]
- Subject: Re: LOADF vs LOADK
- From: Bas Groothedde <lua@...>
- Date: 2020年4月28日 21:31:11 +0200
Dear,
I was looking at the opcodes from lua-5.4.0-rc1 using "luac -l", and
the simple code below
local v1 = 1
local v2 = 1.
local v3 = 1.0
local v4 = 1.01
is translated to
1 [1] VARARGPREP 0
2 [1] LOADI 0 1
3 [2] LOADF 1 1
4 [3] LOADF 2 1
5 [4] LOADK 3 0 ; 1.01
So, why "1." and "1.0" use LOADF but "1.01" uses LOADK?
I think that is caused by the fact LOADF loads the value from the sBx
argument, an integer. In lvm.c, you can see it simply casting sBx as an
int to a lua_Number:
vmcase(OP_LOADF) {
int b = GETARG_sBx(i);
setfltvalue(s2v(ra), cast_num(b));
vmbreak;
}
So I would assume only floating point numbers with an integer value can
be stored in LOADF instructions in the current implementation.
~Bas
_______________________________________________
lua-l mailing list -- lua-l@lists.lua.org
To unsubscribe send an email to lua-l-leave@lists.lua.org