aboutsummaryrefslogtreecommitdiff
path: root/code/asm/matha.s
diff options
context:
space:
mode:
Diffstat (limited to 'code/asm/matha.s')
-rw-r--r--code/asm/matha.s54
1 files changed, 54 insertions, 0 deletions
diff --git a/code/asm/matha.s b/code/asm/matha.s
new file mode 100644
index 0000000..e4770d3
--- /dev/null
+++ b/code/asm/matha.s
@@ -0,0 +1,54 @@
+/*
+===========================================================================
+Copyright (C) 1999-2005 Id Software, Inc.
+
+This file is part of Quake III Arena source code.
+
+Quake III Arena source code is free software; you can redistribute it
+and/or modify it under the terms of the GNU General Public License as
+published by the Free Software Foundation; either version 2 of the License,
+or (at your option) any later version.
+
+Quake III Arena source code is distributed in the hope that it will be
+useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with Foobar; if not, write to the Free Software
+Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+===========================================================================
+*/
+//
+// math.s
+// x86 assembly-language math routines.
+
+#include "qasm.h"
+
+
+#if id386
+
+ .text
+
+// TODO: rounding needed?
+// stack parameter offset
+#define val 4
+
+.globl C(Invert24To16)
+C(Invert24To16):
+
+ movl val(%esp),%ecx
+ movl $0x100,%edx // 0x10000000000 as dividend
+ cmpl %edx,%ecx
+ jle LOutOfRange
+
+ subl %eax,%eax
+ divl %ecx
+
+ ret
+
+LOutOfRange:
+ movl $0xFFFFFFFF,%eax
+ ret
+
+#endif // id386