From: divverent <divverent@d7cf8633-e32d-0410-b094-e92efae38249>
Date: Fri, 14 Aug 2009 19:39:24 +0000 (+0000)
Subject: experimental change: do a float compare for OP_IF and OP_IFNOT, so negative
X-Git-Tag: xonotic-v0.1.0preview~1516
X-Git-Url: https://git.rm.cloudns.org/?a=commitdiff_plain;h=dee17d020970e0a0ac99874899aa4bf406f918a5;p=xonotic%2Fdarkplaces.git

experimental change: do a float compare for OP_IF and OP_IFNOT, so negative
zero float value counts as false. No other value in QC can have the bit pattern
0x80000000 as long as no int type is added.

I have verified that the only false floats on x86_64 and i386 are 0 and
0x80000000.  However, this may fail on other platforms! (but then, OR_F and
others would also fail in some cases, as fteqcc also uses it for "float ||
entity").

When an "int" type is introduced, we'll need a new IF_I and IFNOT_I instruction
as then this would REALLY have a bad impact.


git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@9113 d7cf8633-e32d-0410-b094-e92efae38249
---

diff --git a/prvm_execprogram.h b/prvm_execprogram.h
index 17ea2fcc..19fc6bb3 100644
--- a/prvm_execprogram.h
+++ b/prvm_execprogram.h
@@ -238,7 +238,10 @@
 		//==================
 
 			case OP_IFNOT:
-				if (!OPA->_int)
+				if (!OPA->_float)
+				// TODO add an "int-ifnot"
+				// although mostly unneeded, thanks to the only float being false being 0x0 and 0x80000000 (negative zero)
+				// and entity, string, field values can never have that value
 				{
 					prog->xfunction->profile += (st - startst);
 					st += st->b - 1;	// offset the s++
@@ -255,7 +258,10 @@
 				break;
 
 			case OP_IF:
-				if (OPA->_int)
+				if (OPA->_float)
+				// TODO add an "int-if"
+				// although mostly unneeded, thanks to the only float being false being 0x0 and 0x80000000 (negative zero)
+				// and entity, string, field values can never have that value
 				{
 					prog->xfunction->profile += (st - startst);
 					st += st->b - 1;	// offset the s++