--- trunk/reactos/lib/rtl/i386/math_asm.S 2005-11-30 08:01:56 UTC (rev 19772)
+++ trunk/reactos/lib/rtl/i386/math_asm.S 2005-11-30 08:15:13 UTC (rev 19773)
@@ -69,190 +69,891 @@
__fltused:
.long 0x9875
+.intel_syntax noprefix
+
/* FUNCTIONS ***************************************************************/
-/*
- * long long
- * __alldiv(long long Dividend, long long Divisor)//
- *
- * Parameters:
- * [ESP+04h] - long long Dividend
- * [ESP+0Ch] - long long Divisor
- * Registers:
- * Unknown
- * Returns:
- * EDX:EAX - long long quotient (Dividend/Divisor)
- * Notes:
- * Routine removes the arguments from the stack.
- */
+//
+// lldiv - signed long divide
+//
+// Purpose:
+// Does a signed 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
+//
+
__alldiv:
- call ___divdi3
- ret $0x10
-/*
- * long long
- * __allmul(long long Multiplier, long long Multiplicand)//
- *
- * Parameters:
- * [ESP+04h] - long long Multiplier
- * [ESP+0Ch] - long long Multiplicand
- * Registers:
- * Unknown
- * Returns:
- * EDX:EAX - long long product (Multiplier*Multiplicand)
- * Notes:
- * Routine removes the arguments from the stack.
- */
+ push edi
+ push esi
+ push ebx
+
+// 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 lldiv(a, b)):
+//
+// -----------------
+// | |
+// |---------------|
+// | |
+// |--divisor (b)--|
+// | |
+// |---------------|
+// | |
+// |--dividend (a)-|
+// | |
+// |---------------|
+// | return addr** |
+// |---------------|
+// | EDI |
+// |---------------|
+// | ESI |
+// |---------------|
+// ESP---->| EBX |
+// -----------------
+//
+
+#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 result (edi = 0 if result is positive, non-zero
+// otherwise) and make operands positive.
+
+ xor edi,edi // 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
+ 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 edx,ebx // edx:eax <- quotient
+ jmp short L4 // set sign, restore stack and return
+
+//
+// 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
+L7:
+ xor edx,edx // edx:eax <- quotient
+ 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.
+//
+
+L4:
+ 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 ebx
+ pop esi
+ pop edi
+
+ ret 16
+
+//
+// llmul - long multiply routine
+//
+// Purpose:
+// Does a long multiply (same for signed/unsigned)
+// Parameters are not changed.
+//
+// Entry:
+// Parameters are passed on the stack:
+// 1st pushed: multiplier (QWORD)
+// 2nd pushed: multiplicand (QWORD)
+//
+// Exit:
+// EDX:EAX - product of multiplier and multiplicand
+// NOTE: parameters are removed from the stack
+//
+// Uses:
+// ECX
+//
+
__allmul:
- pushl %ebp
- movl %esp, %ebp
- pushl %edi
- pushl %esi
- pushl %ebx
- subl $12, %esp
- movl 16(%ebp), %ebx
- movl 8(%ebp), %eax
- mull %ebx
- movl 20(%ebp), %ecx
- movl %eax, -24(%ebp)
- movl 8(%ebp), %eax
- movl %edx, %esi
- imull %ecx, %eax
- addl %eax, %esi
- movl 12(%ebp), %eax
- imull %eax, %ebx
- leal (%ebx,%esi), %eax
- movl %eax, -20(%ebp)
- movl -24(%ebp), %eax
- movl -20(%ebp), %edx
- addl $12, %esp
- popl %ebx
- popl %esi
- popl %edi
- popl %ebp
- ret $0x10
-/*
- * unsigned long long
- * __aullrem(unsigned long long Dividend, unsigned long long Divisor)//
- *
- * Parameters:
- * [ESP+04h] - unsigned long long Dividend
- * [ESP+0Ch] - unsigned long long Divisor
- * Registers:
- * Unknown
- * Returns:
- * EDX:EAX - unsigned long long remainder (Dividend%Divisor)
- * Notes:
- * Routine removes the arguments from the stack.
- */
-__aullrem:
- call ___umoddi3
- ret $16
+#define ALO [esp + 4] // stack address of a
+#define AHI [esp + 8] // stack address of a
+#define BLO [esp + 12] // stack address of b
+#define BHI [esp + 16] // stack address of b
-/*
- * long long
- * __allshl(long long Value, unsigned char Shift)//
- *
- * Parameters:
- * EDX:EAX - signed long long value to be shifted left
- * CL - number of bits to shift by
- * Registers:
- * Destroys CL
- * Returns:
- * EDX:EAX - shifted value
- */
+//
+// AHI, BHI : upper 32 bits of A and B
+// ALO, BLO : lower 32 bits of A and B
+//
+// ALO * BLO
+// ALO * BHI
+// + BLO * AHI
+// ---------------------
+//
+
+ mov eax,AHI
+ mov ecx,BHI
+ or ecx,eax //test for both hiwords zero.
+ mov ecx,BLO
+ jnz short hard //both are zero, just mult ALO and BLO
+
+ mov eax,AHI
+ mul ecx
+
+ ret 16 // callee restores the stack
+
+hard:
+ push ebx
+
+// must redefine A and B since esp has been altered
+
+#define A2LO [esp + 4] // stack address of a
+#define A2HI [esp + 8] // stack address of a
+#define B2LO [esp + 12] // stack address of b
+#define B2HI [esp + 16] // stack address of b
+
+ mul ecx //eax has AHI, ecx has BLO, so AHI * BLO
+ mov ebx,eax //save result
+
+ mov eax,A2LO
+ mul dword ptr B2HI //ALO * BHI
+ add ebx,eax //ebx = ((ALO * BHI) + (AHI * BLO))
+
+ mov eax,A2LO //ecx = BLO
+ mul ecx //so edx:eax = ALO*BLO
+ add edx,ebx //now edx has all the LO*HI stuff
+
+ pop ebx
+
+ ret 16 // callee restores the stack
+
+//
+// llrem - signed long remainder
+//
+// Purpose:
+// Does a signed long 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 remainder (dividend%divisor)
+// NOTE: this routine removes the parameters from the stack.
+//
+// Uses:
+// ECX
+//
+
+__allrem :
+
+ push ebx
+ push edi
+
+// 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 lrem(a, b)):
+//
+// -----------------
+// | |
+// |---------------|
+// | |
+// |--divisor (b)--|
+// | |
+// |---------------|
+// | |
+// |--dividend (a)-|
+// | |
+// |---------------|
+// | return addr** |
+// |---------------|
+// | EBX |
+// |---------------|
+// ESP---->| EDI |
+// -----------------
+//
+
+#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)
+
+// Determine sign of the result (edi = 0 if result is positive, non-zero
+// otherwise) and make operands positive.
+
+ xor edi,edi // 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 bit
+ 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
+ mov edx,DVSRLO // lo word of b
+ 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 // edx <- remainder
+ mov eax,DVNDLO // edx:eax <- remainder:lo word of dividend
+ div ecx // edx <- final remainder
+ mov eax,edx // edx:eax <- remainder
+ xor edx,edx
+ dec edi // check result sign flag
+ jns short .L4 // negate result, restore stack and return
+ jmp short .L8 // result sign ok, restore stack and return
+
+//
+// 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
+
+//
+// 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.
+//
+
+ mov ecx,eax // save a copy of quotient in ECX
+ mul dword ptr DVSRHI
+ xchg ecx,eax // save product, get quotient in EAX
+ mul dword ptr 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 the original divisor from the result.
+//
+
+ 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:
+ sub eax,DVSRLO // subtract divisor from result
+ sbb edx,DVSRHI
+.L7:
+
+//
+// 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 edi // check result sign flag
+ jns short .L8 // result is ok, restore stack and return
+.L4:
+ neg edx // otherwise, negate the result
+ neg eax
+ sbb edx,0
+
+//
+// Just the cleanup left to do. edx:eax contains the quotient.
+// Restore the saved registers and return.
+//
+
+.L8:
+ pop edi
+ pop ebx
+
+ ret 16
+
+//
+// llshl - long shift left
+//
+// Purpose:
+// Does a Long Shift Left (signed and unsigned are identical)
+// Shifts a long left any number of bits.
+//
+// Entry:
+// EDX:EAX - long value to be shifted
+// CL - number of bits to shift by
+//
+// Exit:
+// EDX:EAX - shifted value
+//
+// Uses:
+// CL is destroyed.
+//
+
__allshl:
- shldl %cl, %eax, %edx
- sall %cl, %eax
- andl $32, %ecx
- je 1f
- movl %eax, %edx
- xorl %eax, %eax
-1:
- ret
-/*
- * long long
- * __allshr(long long Value, unsigned char Shift)//
- *
- * Parameters:
- * EDX:EAX - signed long long value to be shifted right
- * CL - number of bits to shift by
- * Registers:
- * Destroys CL
- * Returns:
- * EDX:EAX - shifted value
- */
+//
+// Handle shifts of 64 or more bits (all get 0)
+//
+ cmp cl, 64
+ jae short RETZERO
+
+//
+// Handle shifts of between 0 and 31 bits
+//
+ cmp cl, 32
+ jae short MORE32
+ shld edx,eax,cl
+ shl eax,cl
+ ret
+
+//
+// Handle shifts of between 32 and 63 bits
+//
+MORE32:
+ mov edx,eax
+ xor eax,eax
+ and cl,31
+ shl edx,cl
+ ret
+
+//
+// return 0 in edx:eax
+//
+RETZERO:
+ xor eax,eax
+ xor edx,edx
+ ret
+
+//
+// llshr - long shift right
+//
+// Purpose:
+// Does a signed Long Shift Right
+// Shifts a long right any number of bits.
+//
+// Entry:
+// EDX:EAX - long value to be shifted
+// CL - number of bits to shift by
+//
+// Exit:
+// EDX:EAX - shifted value
+//
+// Uses:
+// CL is destroyed.
+//
+
__allshr:
- shrdl %cl, %edx, %eax
- sarl %cl, %edx
- andl $32, %ecx
- je 1f
- movl %edx, %eax
- sarl $31, %edx
-1:
- ret
-/*
- * unsigned long long
- * __aulldiv(unsigned long long Dividend, unsigned long long Divisor)//
- *
- * Parameters:
- * [ESP+04h] - unsigned long long Dividend
- * [ESP+0Ch] - unsigned long long Divisor
- * Registers:
- * Unknown
- * Returns:
- * EDX:EAX - unsigned long long quotient (Dividend/Divisor)
- * Notes:
- * Routine removes the arguments from the stack.
- */
+//
+// Handle shifts of 64 bits or more (if shifting 64 bits or more, the result
+// depends only on the high order bit of edx).
+//
+ cmp cl,64
+ jae short .RETSIGN
+
+//
+// Handle shifts of between 0 and 31 bits
+//
+ cmp cl, 32
+ jae short .MORE32
+ shrd eax,edx,cl
+ sar edx,cl
+ ret
+
+//
+// Handle shifts of between 32 and 63 bits
+//
+.MORE32:
+ mov eax,edx
+ sar edx,31
+ and cl,31
+ sar eax,cl
+ ret
+
+//
+// Return double precision 0 or -1, depending on the sign of edx
+//
+.RETSIGN:
+ sar edx,31
+ mov eax,edx
+ ret
+
+//
+// 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:
- call ___udivdi3
- ret $16
-/*
- * unsigned long long
- * __aullshr(unsigned long long Value, unsigned char Shift)//
- *
- * Parameters:
- * EDX:EAX - unsigned long long value to be shifted right
- * CL - number of bits to shift by
- * Registers:
- * Destroys CL
- * Returns:
- * EDX:EAX - shifted value
- */
+ 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
+
+//
+// ullshr - long shift right
+//
+// Purpose:
+// Does a unsigned Long Shift Right
+// Shifts a long right any number of bits.
+//
+// Entry:
+// EDX:EAX - long value to be shifted
+// CL - number of bits to shift by
+//
+// Exit:
+// EDX:EAX - shifted value
+//
+// Uses:
+// CL is destroyed.
+//
+
__aullshr:
- shrdl %cl, %edx, %eax
- shrl %cl, %edx
- andl $32, %ecx
- je 1f
- movl %edx, %eax
-1:
- ret
-
-/*
- * long long
- * __allrem(long long Dividend, long long Divisor)//
- *
- * Parameters:
- * [ESP+04h] - long long Dividend
- * [ESP+0Ch] - long long Divisor
- * Registers:
- * Unknown
- * Returns:
- * EDX:EAX - long long remainder (Dividend/Divisor)
- * Notes:
- * Routine removes the arguments from the stack.
- */
-__allrem:
- call ___moddi3
- ret $16
-
-.intel_syntax noprefix
+//
+// Handle shifts of 64 bits or more (if shifting 64 bits or more, the result
+// depends only on the high order bit of edx).
+//
+ cmp cl,64
+ jae short ..RETZERO
+
+//
+// Handle shifts of between 0 and 31 bits
+//
+ cmp cl, 32
+ jae short ..MORE32
+ shrd eax,edx,cl
+ shr edx,cl
+ ret
+
+//
+// Handle shifts of between 32 and 63 bits
+//
+..MORE32:
+ mov eax,edx
+ xor edx,edx
+ and cl,31
+ shr eax,cl
+ ret
+
+//
+// return 0 in edx:eax
+//
+..RETZERO:
+ xor eax,eax
+ xor edx,edx
+ ret
+
+//
+// ullrem - unsigned long remainder
+//
+// Purpose:
+// Does a unsigned long 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 remainder (dividend%divisor)
+// NOTE: this routine removes the parameters from the stack.
+//
+// Uses:
+// ECX
+//
+
+__aullrem:
+
+ push ebx
+
+// 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 ullrem(a, b)):
+//
+// -----------------
+// | |
+// |---------------|
+// | |
+// |--divisor (b)--|
+// | |
+// |---------------|
+// | |
+// |--dividend (a)-|
+// | |
+// |---------------|
+// | return addr** |
+// |---------------|
+// ESP---->| EBX |
+// -----------------
+//
+
+#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 // edx <- remainder, eax <- quotient
+ mov eax,DVNDLO // edx:eax <- remainder:lo word of dividend
+ div ecx // edx <- final remainder
+ mov eax,edx // edx:eax <- remainder
+ xor edx,edx
+ 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:
[truncated at 1000 lines; 365 more skipped]