[ros-diffs] [turner] 19931: Actually provide __aulldiv code.
turner at svn.reactos.com
turner at svn.reactos.com
Tue Dec 6 17:41:57 CET 2005
Actually provide __aulldiv code.
Added: trunk/reactos/lib/rtl/i386/aulldiv_asm.s
Modified: trunk/reactos/lib/rtl/rtl.xml
_____
Added: trunk/reactos/lib/rtl/i386/aulldiv_asm.s
--- trunk/reactos/lib/rtl/i386/aulldiv_asm.s 2005-12-06 14:38:20 UTC
(rev 19930)
+++ trunk/reactos/lib/rtl/i386/aulldiv_asm.s 2005-12-06 16:41:53 UTC
(rev 19931)
@@ -0,0 +1,180 @@
+/*
+ * COPYRIGHT: See COPYING in the top level directory
+ * PROJECT: ReactOS kernel
+ * PURPOSE: Run-Time Library
+ * FILE: lib/rtl/i386/aulldiv_asm.S
+ * PROGRAMER: Alex Ionescu (alex at relsoft.net)
+ * Eric Kohl (ekohl at rz-online.de)
+ *
+ * Copyright (C) 2002 Michael Ringgaard.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
the
+ * documentation and/or other materials provided with the
distribution.
+ * 3. Neither the name of the project nor the names of its contributors
+ * may be used to endorse or promote products derived from this
software
+ * without specific prior written permission.
+
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
GOODS
+ * OR SERVICES// LOSS OF USE, DATA, OR PROFITS// OR BUSINESS
INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
OF
+ * SUCH DAMAGE.
+ */
+
+ .globl __aulldiv
+
+.intel_syntax noprefix
+
+/* FUNCTIONS
***************************************************************/
+
+//
+// ulldiv - unsigned long divide
+//
+// Purpose:
+// Does a unsigned long divide of the arguments. Arguments are
+// not changed.
+//
+// Entry:
+// Arguments are passed on the stack:
+// 1st pushed: divisor (QWORD)
+// 2nd pushed: dividend (QWORD)
+//
+// Exit:
+// EDX:EAX contains the quotient (dividend/divisor)
+// NOTE: this routine removes the parameters from the stack.
+//
+// Uses:
+// ECX
+//
+
+__aulldiv:
+
+ push ebx
+ push esi
+
+// Set up the local stack and save the index registers. When this is
done
+// the stack frame will look as follows (assuming that the expression
a/b will
+// generate a call to uldiv(a, b)):
+//
+// -----------------
+// | |
+// |---------------|
+// | |
+// |--divisor (b)--|
+// | |
+// |---------------|
+// | |
+// |--dividend (a)-|
+// | |
+// |---------------|
+// | return addr** |
+// |---------------|
+// | EBX |
+// |---------------|
+// ESP---->| ESI |
+// -----------------
+//
+
+#undef DVNDLO
+#undef DVNDHI
+#undef DVSRLO
+#undef DVSRHI
+#define DVNDLO [esp + 12] // stack address of dividend (a)
+#define DVNDHI [esp + 16] // stack address of dividend (a)
+#define DVSRLO [esp + 20] // stack address of divisor (b)
+#define DVSRHI [esp + 24] // stack address of divisor (b)
+
+//
+// Now do the divide. First look to see if the divisor is less than
4194304K.
+// If so, then we can use a simple algorithm with word divides,
otherwise
+// things get a little more complex.
+//
+
+ mov eax,DVSRHI // check to see if divisor < 4194304K
+ or eax,eax
+ jnz short ..L1 // nope, gotta do this the hard way
+ mov ecx,DVSRLO // load divisor
+ mov eax,DVNDHI // load high word of dividend
+ xor edx,edx
+ div ecx // get high order bits of quotient
+ mov ebx,eax // save high bits of quotient
+ mov eax,DVNDLO // edx:eax <- remainder:lo word of dividend
+ div ecx // get low order bits of quotient
+ mov edx,ebx // edx:eax <- quotient hi:quotient lo
+ jmp short ..L2 // restore stack and return
+
+//
+// Here we do it the hard way. Remember, eax contains DVSRHI
+//
+
+..L1:
+ mov ecx,eax // ecx:ebx <- divisor
+ mov ebx,DVSRLO
+ mov edx,DVNDHI // edx:eax <- dividend
+ mov eax,DVNDLO
+..L3:
+ shr ecx,1 // shift divisor right one bit// hi bit
<- 0
+ rcr ebx,1
+ shr edx,1 // shift dividend right one bit// hi
bit <- 0
+ rcr eax,1
+ or ecx,ecx
+ jnz short ..L3 // loop until divisor < 4194304K
+ div ebx // now divide, ignore remainder
+ mov esi,eax // save quotient
+
+//
+// We may be off by one, so to check, we will multiply the quotient
+// by the divisor and check the result against the orignal dividend
+// Note that we must also check for overflow, which can occur if the
+// dividend is close to 2**64 and the quotient is off by 1.
+//
+
+ mul dword ptr DVSRHI // QUOT * DVSRHI
+ mov ecx,eax
+ mov eax,DVSRLO
+ mul esi // QUOT * DVSRLO
+ add edx,ecx // EDX:EAX = QUOT * DVSR
+ jc short ..L4 // carry means Quotient is off by 1
+
+//
+// do long compare here between original dividend and the result of the
+// multiply in edx:eax. If original is larger or equal, we are ok,
otherwise
+// subtract one (1) from the quotient.
+//
+
+ cmp edx,DVNDHI // compare hi words of result and original
+ ja short ..L4 // if result > original, do subtract
+ jb short ..L5 // if result < original, we are ok
+ cmp eax,DVNDLO // hi words are equal, compare lo words
+ jbe short ..L5 // if less or equal we are ok, else
subtract
+..L4:
+ dec esi // subtract 1 from quotient
+..L5:
+ xor edx,edx // edx:eax <- quotient
+ mov eax,esi
+
+//
+// Just the cleanup left to do. edx:eax contains the quotient.
+// Restore the saved registers and return.
+//
+
+..L2:
+
+ pop esi
+ pop ebx
+
+ ret 16
_____
Modified: trunk/reactos/lib/rtl/rtl.xml
--- trunk/reactos/lib/rtl/rtl.xml 2005-12-06 14:38:20 UTC (rev
19930)
+++ trunk/reactos/lib/rtl/rtl.xml 2005-12-06 16:41:53 UTC (rev
19931)
@@ -15,6 +15,7 @@
<file>allshl_asm.s</file>
<file>allshr_asm.s</file>
<file>atan_asm.s</file>
+ <file>aulldiv_asm.s</file>
<file>aulldvrm_asm.s</file>
<file>aullrem_asm.s</file>
<file>aullshr_asm.s</file>
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