Assembler:Commands:IMUL - Revision history

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TheyCallMeTim13: /* Examples */

2018-01-17T22:24:45Z

‎Examples

TheyCallMeTim13 at 15:46, 3 January 2018

2018-01-03T15:46:04Z

TheyCallMeTim13 at 15:22, 3 January 2018

2018-01-03T15:22:05Z

TheyCallMeTim13 at 22:08, 19 March 2017

2017-03-19T22:08:57Z

TheyCallMeTim13 at 11:26, 19 March 2017

2017-03-19T11:26:26Z

TheyCallMeTim13 at 04:30, 15 March 2017

2017-03-15T04:30:31Z

TheyCallMeTim13 at 04:12, 15 March 2017

2017-03-15T04:12:02Z

TheyCallMeTim13: Created page with ''''command''' imul ''destination'', ''source1'', ''source2'' Performs a signed multiplication of two or three operands. This instruction has three forms, depending on the number…'

2017-03-15T02:39:18Z

Created page with ''''command''' imul ''destination'', ''source1'', ''source2'' Performs a signed multiplication of two or three operands. This instruction has three forms, depending on the number…'

New page

'''command''' imul ''destination'', ''source1'', ''source2''

Performs a signed multiplication of two or three operands. This instruction has three forms, depending on the number of operands.

; One-operand
: This form is identical to that used by the [[Assembler:Commands:MUL|MUL]] instruction, just signed. Here, the source operand (in a general-purpose register or memory location) is multiplied by the value in the accumulator register and the upper product is stored in the data register and lower product is stored in the accumulator register.
: The '''CF''' and '''OF''' flags are set when significant bits are carried into the upper half of the result and cleared when the result fits exactly in the lower half of the result.

; Two-operand
: With this form the destination operand (the first operand) is multiplied by the source operand (second operand). The destination operand is a general purpose register and the source operand is an immediate value, a general-purpose register, or a memory location. The product is then stored in the destination operand location.
: The '''CF''' and '''OF''' flags are set when the result must be truncated to fit in the destination operand size and cleared when the result fits exactly in the destination operand size. The '''SF''', '''ZF''', '''AF''', and '''PF''' flags are undefined.

; Three-operand
: This form requires a destination operand (the first operand) and two source operands (the second and the third operands). Here, the first source operand (which can be a general-purpose register or a memory location) is multiplied by the second source operand (an immediate value). The product is then stored in the destination operand (a general-purpose register).
: The '''CF''' and '''OF''' flags are set when the result must be truncated to fit in the destination operand size and cleared when the result fits exactly in the destination operand size. The '''SF''', '''ZF''', '''AF''', and '''PF''' flags are undefined.

<div style="padding:2px;border:1px dashed #2f6fab;background-color:#f4f4f4;">
Performs a signed multiplication of two operands. This instruction has three forms, depending on the number of operands.

One-operand form. This form is identical to that used by the [[Assembler:Commands:MUL|MUL]] instruction. Here, the source operand (in a general-purpose register or memory location) is multiplied by the value in the AL, AX, or EAX register (depending on the operand size) and the product is stored in the AX, (E)DX:(E)AX.

Two-operand form. With this form the destination operand (the first operand) is multiplied by the source operand (second operand). The destination operand is a general purpose register and the source operand is an immediate value, a general-purpose register, or a memory location. The product is then stored in the destination operand location.

Three-operand form. This form requires a destination operand (the first operand) and two source operands (the second and the third operands). Here, the first source operand (which can be a general-purpose register or a memory location) is multiplied by the second source operand (an immediate value). The product is then stored in the destination operand (a general-purpose register).

When an immediate value is used as an operand, it is sign-extended to the length of the destination operand format.

The CF and OF flags are set when significant bit (including the sign bit) are carried into the upper half of the result. The CF and OF flags are cleared when the result (including the sign bit) fits exactly in the lower half of the result.

The three forms of the IMUL instruction are similar in that the length of the product is calculated to twice the length of the operands. With the one-operand form, the product is stored exactly in the destination. With the two- and three- operand forms, however, the result is truncated to the length of the destination before it is stored in the destination register. Because of this truncation, the CF or OF flag should be tested to ensure that no significant bits are lost.

The two- and three-operand forms may also be used with unsigned operands because the lower half of the product is the same regardless if the operands are signed or unsigned. The CF and OF flags, however, cannot be used to determine if the upper half of the result is non-zero.

[http://x86.renejeschke.de/html/file_module_x86_id_138.html x86.renejeschke.de/html/file_module_x86_id_138.html]
</div>

=== Command Parameters ===
{|width="85%" cellpadding="10%" cellpadding="5%" cellspacing="0" border="0"
!align="left"|Parameter
!style="width: 80%;background-color:white;" align="left"|Description
|-
|destination
|The destination multiplier operand
|-
|source1 '''Optional'''
|The first source multiplier operand
|-
|source2 '''Optional'''
|The second source multiplier operand
|}

== Examples ==
imul ecx // eax = eax * ecx

imul ecx,2 // ecx = ecx * 2

imul ecx,edx,2 // ecx = ecx * 2

mov eax,3
mov ecx,2
imul ecx // ecx = eax * ecx
// edx = 0, eax = 6, edx:eax = 6

mov eax,3
mov ecx,2
imul eax,ecx // eax = eax * ecx
// eax = 6

mov eax,10
mov ecx,3
imul eax,ecx,2 // eax = ecx * 2
// eax = 6

== See also ==
* [[Assembler]]
* [[Cheat_Engine:Auto Assembler|Auto Assembler]]
* [[Assembler:Commands|Assembler Commands]]

== External links ==
* [https://wikipedia.org/wiki/X86_instruction_listings wikipedia.org/wiki/X86_instruction_listings]
* [https://wikibooks.org/wiki/X86_Assembly/Other_Instructions wikibooks.org/wiki/X86_Assembly/Other_Instructions]
* [http://www.asmpedia.org/index.php?title=Main_Page asmpedia.org]

← Older revision		Revision as of 16:15, 16 March 2019
Line 1:		Line 1:
−	~~[[Category:Assembler]]~~	+	<span style="font-size:25px;color:red">Sorry! Content not available.</span>
−	~~'''command''' imul ''destination'', ''source1'', ''source2''~~
−
−	~~Performs a signed multiplication of two or three operands. This instruction has three forms, depending on the number of operands.~~
−
−	~~; One-operand~~
−	: This form is identical to that used by the [[Assembler:Commands:MUL\|MUL]] instruction, just signed. Here, the source operand (in a general-purpose register or memory location) is multiplied by the value in the accumulator register and the upper product is stored in the data register and lower product is stored in the accumulator register.
−	~~: The '''CF''' and '''OF''' flags are set when significant bits are carried into the upper half of the result and cleared when the result fits exactly in the lower half of the result.~~
−
−	~~; Two-operand~~
−	: With this form the destination operand (the first operand) is multiplied by the source operand (second operand). The destination operand is a general purpose register and the source operand is an immediate value, a general-purpose register, or a memory location. The product is then stored in the destination operand location.
−	: The '''CF''' and '''OF''' flags are set when the result must be truncated to fit in the destination operand size and cleared when the result fits exactly in the destination operand size. The '''SF''', '''ZF''', '''AF''', and '''PF''' flags are undefined.
−
−	~~; Three-operand~~
−	: This form requires a destination operand (the first operand) and two source operands (the second and the third operands). Here, the first source operand (which can be a general-purpose register or a memory location) is multiplied by the second source operand (an immediate value). The product is then stored in the destination operand (a general-purpose register).
−	: The '''CF''' and '''OF''' flags are set when the result must be truncated to fit in the destination operand size and cleared when the result fits exactly in the destination operand size. The '''SF''', '''ZF''', '''AF''', and '''PF''' flags are undefined.
−
−
−	<~~div~~ style="~~padding~~:~~2px~~;~~border:1px dashed #2f6fab;background-~~color:~~#f4f4f4;~~">
−	~~Performs a signed multiplication of two operands. This instruction has three forms, depending on the number of operands.~~
−
−	One-operand form. This form is identical to that used by the [[Assembler:Commands:MUL\|MUL]] instruction. Here, the source operand (in a general-purpose register or memory location) is multiplied by the value in the AL, AX, or EAX register (depending on the operand size) and the product is stored in the AX, (E)DX:(E)AX.
−
−	Two-operand form. With this form the destination operand (the first operand) is multiplied by the source operand (second operand). The destination operand is a general purpose register and the source operand is an immediate value, a general-purpose register, or a memory location. The product is then stored in the destination operand location.
−
−	Three-operand form. This form requires a destination operand (the first operand) and two source operands (the second and the third operands). Here, the first source operand (which can be a general-purpose register or a memory location) is multiplied by the second source operand (an immediate value). The product is then stored in the destination operand (a general-purpose register).
−
−	~~When an immediate value is used as an operand, it is sign-extended to the length of the destination operand format.~~
−
−	The CF and OF flags are set when significant bit (including the sign bit) are carried into the upper half of the result. The CF and OF flags are cleared when the result (including the sign bit) fits exactly in the lower half of the result.
−
−	The three forms of the IMUL instruction are similar in that the length of the product is calculated to twice the length of the operands. With the one-operand form, the product is stored exactly in the destination. With the two- and three- operand forms, however, the result is truncated to the length of the destination before it is stored in the destination register. Because of this truncation, the CF or OF flag should be tested to ensure that no significant bits are lost.
−
−	The two- and three-operand forms may also be used with unsigned operands because the lower half of the product is the same regardless if the operands are signed or unsigned. The CF and OF flags, however, cannot be used to determine if the upper half of the result is non-zero.
−
−	~~[http://c9x.me/x86/html/file_module_x86_id_138~~.~~html c9x.me/x86/html/file_module_x86_id_138.html]~~
−	</~~div~~>
−
−
−	~~=== Command Parameters ===~~
−	~~{\|width="85%" cellpadding="10%" cellpadding="5%" cellspacing="0" border="0"~~
−	~~!align="left"\|Parameter~~
−	~~!style="width: 80%;background-color:white;" align="left"\|Description~~
−	\|-
−	~~\|destination~~
−	~~\|The destination multiplier operand~~
−	\|-
−	~~\|source1 '''Optional'''~~
−	~~\|The first source multiplier operand~~
−	\|-
−	~~\|source2 '''Optional'''~~
−	~~\|The second source multiplier operand~~
−	\|}
−
−
−	~~== Examples ==~~
−	~~imul ecx // eax = eax * ecx~~
−
−	~~imul ecx,2 // ecx = ecx * 2~~
−
−	~~imul ecx,edx,2 // ecx = edx * 2~~
−
−	~~mov eax,3~~
−	~~mov ecx,2~~
−	~~imul ecx // ecx = eax * ecx~~
−	~~// edx = 0, eax = 6, edx:eax = 6~~
−
−	~~mov eax,3~~
−	~~mov ecx,2~~
−	~~imul eax,ecx // eax = eax * ecx~~
−	~~// eax = 6~~
−
−	~~mov eax,10~~
−	~~mov ecx,3~~
−	~~imul eax,ecx,2 // eax = ecx * 2~~
−	~~// eax = 6~~
−
−	~~{{AssemblerCommandSeeAlso}}~~
−
−	~~{{Template:AssemblerCommandExternalLinks}}~~

← Older revision		Revision as of 15:46, 3 January 2018
Line 34:		Line 34:
	The two- and three-operand forms may also be used with unsigned operands because the lower half of the product is the same regardless if the operands are signed or unsigned. The CF and OF flags, however, cannot be used to determine if the upper half of the result is non-zero.		The two- and three-operand forms may also be used with unsigned operands because the lower half of the product is the same regardless if the operands are signed or unsigned. The CF and OF flags, however, cannot be used to determine if the upper half of the result is non-zero.

		+	[http://c9x.me/x86/html/file_module_x86_id_138.html c9x.me/x86/html/file_module_x86_id_138.html]
	</div>		</div>

@@ Line 34: / Line 34: @@
 The two- and three-operand forms may also be used with unsigned operands because the lower half of the product is the same regardless if the operands are signed or unsigned. The CF and OF flags, however, cannot be used to determine if the upper half of the result is non-zero.
 </div>
@@ Line 78: / Line 77: @@
 {{AssemblerCommandSeeAlso}}
-== External links ==
+{{Template:AssemblerCommandExternalLinks}}

← Older revision		Revision as of 11:26, 19 March 2017
Line 1:		Line 1:
		+	[[Category:Assembler]]
	'''command''' imul ''destination'', ''source1'', ''source2''		'''command''' imul ''destination'', ''source1'', ''source2''

← Older revision		Revision as of 04:30, 15 March 2017
Line 85:		Line 85:
	* [http://x86.renejeschke.de/ x86.renejeschke.de]		* [http://x86.renejeschke.de/ x86.renejeschke.de]
	* [http://www.asmpedia.org/index.php?title=Main_Page asmpedia.org]		* [http://www.asmpedia.org/index.php?title=Main_Page asmpedia.org]
		+	* [http://ref.x86asm.net/ ref.x86asm.net]

← Older revision		Revision as of 19:09, 18 March 2019
Line 1:		Line 1:
−	<~~span~~ style="~~font-size~~:~~25px~~;color:~~red~~">~~Sorry! Content not available~~.</~~span~~>	+	[[Category:Assembler]]
		+	'''command''' imul ''destination'', ''source1'', ''source2''
		+
		+	Performs a signed multiplication of two or three operands. This instruction has three forms, depending on the number of operands.
		+
		+	; One-operand
		+	: This form is identical to that used by the [[Assembler:Commands:MUL\|MUL]] instruction, just signed. Here, the source operand (in a general-purpose register or memory location) is multiplied by the value in the accumulator register and the upper product is stored in the data register and lower product is stored in the accumulator register.
		+	: The '''CF''' and '''OF''' flags are set when significant bits are carried into the upper half of the result and cleared when the result fits exactly in the lower half of the result.
		+
		+	; Two-operand
		+	: With this form the destination operand (the first operand) is multiplied by the source operand (second operand). The destination operand is a general purpose register and the source operand is an immediate value, a general-purpose register, or a memory location. The product is then stored in the destination operand location.
		+	: The '''CF''' and '''OF''' flags are set when the result must be truncated to fit in the destination operand size and cleared when the result fits exactly in the destination operand size. The '''SF''', '''ZF''', '''AF''', and '''PF''' flags are undefined.
		+
		+	; Three-operand
		+	: This form requires a destination operand (the first operand) and two source operands (the second and the third operands). Here, the first source operand (which can be a general-purpose register or a memory location) is multiplied by the second source operand (an immediate value). The product is then stored in the destination operand (a general-purpose register).
		+	: The '''CF''' and '''OF''' flags are set when the result must be truncated to fit in the destination operand size and cleared when the result fits exactly in the destination operand size. The '''SF''', '''ZF''', '''AF''', and '''PF''' flags are undefined.
		+
		+
		+	<div style="padding:2px;border:1px dashed #2f6fab;background-color:#f4f4f4;">
		+	Performs a signed multiplication of two operands. This instruction has three forms, depending on the number of operands.
		+
		+	One-operand form. This form is identical to that used by the [[Assembler:Commands:MUL\|MUL]] instruction. Here, the source operand (in a general-purpose register or memory location) is multiplied by the value in the AL, AX, or EAX register (depending on the operand size) and the product is stored in the AX, (E)DX:(E)AX.
		+
		+	Two-operand form. With this form the destination operand (the first operand) is multiplied by the source operand (second operand). The destination operand is a general purpose register and the source operand is an immediate value, a general-purpose register, or a memory location. The product is then stored in the destination operand location.
		+
		+	Three-operand form. This form requires a destination operand (the first operand) and two source operands (the second and the third operands). Here, the first source operand (which can be a general-purpose register or a memory location) is multiplied by the second source operand (an immediate value). The product is then stored in the destination operand (a general-purpose register).
		+
		+	When an immediate value is used as an operand, it is sign-extended to the length of the destination operand format.
		+
		+	The CF and OF flags are set when significant bit (including the sign bit) are carried into the upper half of the result. The CF and OF flags are cleared when the result (including the sign bit) fits exactly in the lower half of the result.
		+
		+	The three forms of the IMUL instruction are similar in that the length of the product is calculated to twice the length of the operands. With the one-operand form, the product is stored exactly in the destination. With the two- and three- operand forms, however, the result is truncated to the length of the destination before it is stored in the destination register. Because of this truncation, the CF or OF flag should be tested to ensure that no significant bits are lost.
		+
		+	The two- and three-operand forms may also be used with unsigned operands because the lower half of the product is the same regardless if the operands are signed or unsigned. The CF and OF flags, however, cannot be used to determine if the upper half of the result is non-zero.
		+
		+	[http://c9x.me/x86/html/file_module_x86_id_138.html c9x.me/x86/html/file_module_x86_id_138.html]
		+	</div>
		+
		+
		+	=== Command Parameters ===
		+	{\|width="85%" cellpadding="10%" cellpadding="5%" cellspacing="0" border="0"
		+	!align="left"\|Parameter
		+	!style="width: 80%;background-color:white;" align="left"\|Description
		+	\|-
		+	\|destination
		+	\|The destination multiplier operand
		+	\|-
		+	\|source1 '''Optional'''
		+	\|The first source multiplier operand
		+	\|-
		+	\|source2 '''Optional'''
		+	\|The second source multiplier operand
		+	\|}
		+
		+
		+	== Examples ==
		+	imul ecx // eax = eax * ecx
		+
		+	imul ecx,2 // ecx = ecx * 2
		+
		+	imul ecx,edx,2 // ecx = edx * 2
		+
		+	mov eax,3
		+	mov ecx,2
		+	imul ecx // ecx = eax * ecx
		+	// edx = 0, eax = 6, edx:eax = 6
		+
		+	mov eax,3
		+	mov ecx,2
		+	imul eax,ecx // eax = eax * ecx
		+	// eax = 6
		+
		+	mov eax,10
		+	mov ecx,3
		+	imul eax,ecx,2 // eax = ecx * 2
		+	// eax = 6
		+
		+	{{AssemblerCommandSeeAlso}}
		+
		+	{{Template:AssemblerCommandExternalLinks}}

@@ Line 59: / Line 59: @@
   imul ecx,2 // ecx = ecx * 2
-  imul ecx,edx,2 // ecx = ecx * 2
+  imul ecx,edx,2 // ecx = edx * 2
   mov eax,3

@@ Line 76: / Line 76: @@
   // eax = 6
-== See also ==
+{{AssemblerCommandSeeAlso}}
 == External links ==

@@ Line 83: / Line 83: @@
 * [https://wikipedia.org/wiki/X86_instruction_listings wikipedia.org/wiki/X86_instruction_listings]
 * [https://wikibooks.org/wiki/X86_Assembly/Other_Instructions wikibooks.org/wiki/X86_Assembly/Other_Instructions]
 * [http://www.asmpedia.org/index.php?title=Main_Page asmpedia.org]