--- trunk/reactos/lib/rtl/i386/math.S 2005-09-26 20:52:20 UTC (rev 18109)
+++ trunk/reactos/lib/rtl/i386/math.S 2005-09-26 21:39:04 UTC (rev 18110)
@@ -5,7 +5,34 @@
* FILE: lib/rtl/i386/math.S
* PROGRAMER: Alex Ionescu (alex@relsoft.net)
* Eric Kohl (ekohl@rz-online.de)
- * REVISION HISTORY: 27/07/2005 Created
+ *
+ * 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.
*/
/* GLOBALS ****************************************************************/
@@ -19,6 +46,8 @@
.globl __aullrem
.globl __allmul
.globl __alldiv
+.globl __aulldvrm
+.globl __alldvrm
/* FUNCTIONS ***************************************************************/
@@ -235,3 +264,368 @@
/* Remove stack frame and return*/
leave
ret
+
+__alldvrm:
+ push edi
+ push esi
+ push ebp
+
+// 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 alldvrm(a, b)):
+//
+// -----------------
+// | |
+// |---------------|
+// | |
+// |--divisor (b)--|
+// | |
+// |---------------|
+// | |
+// |--dividend (a)-|
+// | |
+// |---------------|
+// | return addr** |
+// |---------------|
+// | EDI |
+// |---------------|
+// | ESI |
+// |---------------|
+// ESP---->| EBP |
+// -----------------
+//
+
+#define DVNDLO [esp + 16] // stack address of dividend (a)
+#define DVNDHI [esp + 20] // stack address of dividend (a)
+#define DVSRLO [esp + 24] // stack address of divisor (b)
+#define DVSRHI [esp + 28] // stack address of divisor (b)
+
+// Determine sign of the quotient (edi = 0 if result is positive, non-zero
+// otherwise) and make operands positive.
+// Sign of the remainder is kept in ebp.
+
+ xor edi,edi // result sign assumed positive
+ xor ebp,ebp // result sign assumed positive
+
+ mov eax,DVNDHI // hi word of a
+ or eax,eax // test to see if signed
+ jge short L1 // skip rest if a is already positive
+ inc edi // complement result sign flag
+ inc ebp // complement result sign flag
+ mov edx,DVNDLO // lo word of a
+ neg eax // make a positive
+ neg edx
+ sbb eax,0
+ mov DVNDHI,eax // save positive value
+ mov DVNDLO,edx
+L1:
+ mov eax,DVSRHI // hi word of b
+ or eax,eax // test to see if signed
+ jge short L2 // skip rest if b is already positive
+ inc edi // complement the result sign flag
+ mov edx,DVSRLO // lo word of a
+ neg eax // make b positive
+ neg edx
+ sbb eax,0
+ mov DVSRHI,eax // save positive value
+ mov DVSRLO,edx
+L2:
+
+//
+// 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.
+//
+// NOTE - eax currently contains the high order word of DVSR
+//
+
+ or eax,eax // check to see if divisor < 4194304K
+ jnz short L3 // 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 // eax <- 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 // eax <- low order bits of quotient
+ mov esi,eax // ebx:esi <- quotient
+//
+// Now we need to do a multiply so that we can compute the remainder.
+//
+ mov eax,ebx // set up high word of quotient
+ mul dword ptr DVSRLO // HIWORD(QUOT) * DVSR
+ mov ecx,eax // save the result in ecx
+ mov eax,esi // set up low word of quotient
+ mul dword ptr DVSRLO // LOWORD(QUOT) * DVSR
+ add edx,ecx // EDX:EAX = QUOT * DVSR
+ jmp short L4 // complete remainder calculation
+
+//
+// Here we do it the hard way. Remember, eax contains the high word of DVSR
+//
+
+L3:
+ mov ebx,eax // ebx:ecx <- divisor
+ mov ecx,DVSRLO
+ mov edx,DVNDHI // edx:eax <- dividend
+ mov eax,DVNDLO
+L5:
+ shr ebx,1 // shift divisor right one bit
+ rcr ecx,1
+ shr edx,1 // shift dividend right one bit
+ rcr eax,1
+ or ebx,ebx
+ jnz short L5 // loop until divisor < 4194304K
+ div ecx // 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 L6 // 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 L6 // if result > original, do subtract
+ jb short L7 // if result < original, we are ok
+ cmp eax,DVNDLO // hi words are equal, compare lo words
+ jbe short L7 // if less or equal we are ok, else subtract
+L6:
+ dec esi // subtract 1 from quotient
+ sub eax,DVSRLO // subtract divisor from result
+ sbb edx,DVSRHI
+L7:
+ xor ebx,ebx // ebx:esi <- quotient
+
+L4:
+//
+// Calculate remainder by subtracting the result from the original dividend.
+// Since the result is already in a register, we will do the subtract in the
+// opposite direction and negate the result if necessary.
+//
+
+ sub eax,DVNDLO // subtract dividend from result
+ sbb edx,DVNDHI
+
+//
+// Now check the result sign flag to see if the result is supposed to be positive
+// or negative. It is currently negated (because we subtracted in the 'wrong'
+// direction), so if the sign flag is set we are done, otherwise we must negate
+// the result to make it positive again.
+//
+
+ dec ebp // check result sign flag
+ jns short L9 // result is ok, set up the quotient
+ neg edx // otherwise, negate the result
+ neg eax
+ sbb edx,0
+
+//
+// Now we need to get the quotient into edx:eax and the remainder into ebx:ecx.
+//
+L9:
+ mov ecx,edx
+ mov edx,ebx
+ mov ebx,ecx
+ mov ecx,eax
+ mov eax,esi
+
+//
+// Just the cleanup left to do. edx:eax contains the quotient. Set the sign
+// according to the save value, cleanup the stack, and return.
+//
+
+ dec edi // check to see if result is negative
+ jnz short L8 // if EDI == 0, result should be negative
+ neg edx // otherwise, negate the result
+ neg eax
+ sbb edx,0
+
+//
+// Restore the saved registers and return.
+//
+
+L8:
+ pop ebp
+ pop esi
+ pop edi
+
+ ret 16
+
+__aulldvrm:
+
+// ulldvrm - unsigned long divide and remainder
+//
+// Purpose:
+// Does a unsigned long divide and remainder 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)
+// EBX:ECX contains the remainder (divided % divisor)
+// NOTE: this routine removes the parameters from the stack.
+//
+// Uses:
+// ECX
+//
+ 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 aulldvrm(a, b)):
+//
+// -----------------
+// | |
+// |---------------|
+// | |
+// |--divisor (b)--|
+// | |
+// |---------------|
+// | |
+// |--dividend (a)-|
+// | |
+// |---------------|
+// | return addr** |
+// |---------------|
+// ESP---->| ESI |
+// -----------------
+//
+
+#undef DVNDLO
+#undef DVNDHI
+#undef DVSRLO
+#undef DVSRHI
+#define DVNDLO [esp + 8] // stack address of dividend (a)
+#define DVNDHI [esp + 8] // stack address of dividend (a)
+#define DVSRLO [esp + 16] // stack address of divisor (b)
+#define DVSRHI [esp + 20] // 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 esi,eax // ebx:esi <- quotient
+
+//
+// Now we need to do a multiply so that we can compute the remainder.
+//
+ mov eax,ebx // set up high word of quotient
+ mul dword ptr DVSRLO // HIWORD(QUOT) * DVSR
+ mov ecx,eax // save the result in ecx
+ mov eax,esi // set up low word of quotient
+ mul dword ptr DVSRLO // LOWORD(QUOT) * DVSR
+ add edx,ecx // EDX:EAX = QUOT * DVSR
+ jmp short .L2 // complete remainder calculation
+
+//
+// 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
+ sub eax,DVSRLO // subtract divisor from result
+ sbb edx,DVSRHI
+.L5:
+ xor ebx,ebx // ebx:esi <- quotient
+
+.L2:
+//
+// Calculate remainder by subtracting the result from the original dividend.
+// Since the result is already in a register, we will do the subtract in the
+// opposite direction and negate the result.
+//
+
+ sub eax,DVNDLO // subtract dividend from result
+ sbb edx,DVNDHI
+ neg edx // otherwise, negate the result
+ neg eax
+ sbb edx,0
+
+//
+// Now we need to get the quotient into edx:eax and the remainder into ebx:ecx.
+//
+ mov ecx,edx
+ mov edx,ebx
+ mov ebx,ecx
+ mov ecx,eax
+ mov eax,esi
+//
+// Just the cleanup left to do. edx:eax contains the quotient.
+// Restore the saved registers and return.
+//
+
+ pop esi
+
+ ret 16
+