MantisBT - Cheat Engine
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0000102Cheat Enginepublic2009-02-06 21:142009-02-07 10:32
ReporterCsimbi 
Assigned To 
PrioritynormalSeverityblockReproducibilityalways
StatusconfirmedResolutionopen 
PlatformOSOS Version
Summary0000102: CE 5.5 Valid ASM instruction not accepted
DescriptionHi there,
I am writing a script, which includes the imul instruction.
CE does not accept the instruction - even though it is OK, according to Intel.
This is my instruction:
imul eax,0A
The error is shown on the screen shot that I attached.
Additional InformationInteläs instruction set reference says (quote):
Opcode Instruction Description
F6 /5 IMUL r/m8 AX? AL ? r/m byte.
F7 /5 IMUL r/m16 DX:AX ? AX ? r/m word.
F7 /5 IMUL r/m32 EDX:EAX ? EAX ? r/m doubleword.
0F AF /r IMUL r16,r/m16 word register ? word register ? r/m word.
0F AF /r IMUL r32,r/m32 doubleword register ? doubleword register ? r/m
doubleword.
6B /r ib IMUL r16,r/m16,imm8 word register ? r/m16 ? sign-extended immediate byte.
6B /r ib IMUL r32,r/m32,imm8 doubleword register ? r/m32 ? sign-extended immediate
byte.
6B /r ib IMUL r16,imm8 word register ? word register ? sign-extended immediate
byte.
6B /r ib IMUL r32,imm8 doubleword register ? doubleword register ? signextended
immediate byte.
69 /r iw IMUL r16,r/
m16,imm16
word register ? r/m16 ? immediate word.
69 /r id IMUL r32,r/
m32,imm32
doubleword register ? r/m32 ? immediate doubleword.
69 /r iw IMUL r16,imm16 word register ? r/m16 ? immediate word.
69 /r id IMUL r32,imm32 doubleword register ? r/m32 ? immediate doubleword.

Description
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 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, DX:AX, or EDX:EAX registers, respectively.
• 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.

According to this, the "Two-operand form" should work.
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Attached Files

Notes
(0000224)
Csimbi   
2009-02-06 21:17   
(Last edited: 2009-02-06 21:19)
For now - as a workaround - I put this there:
imul eax,eax,0A
This one is accepted.

(0000228)
Dark Byte   
2009-02-07 10:32   
managed to reproduce but no idea where it comes from

Issue History
2009-02-06 21:14CsimbiNew Issue
2009-02-06 21:14CsimbiFile Added: ERROR.PNG
2009-02-06 21:17CsimbiNote Added: 0000224
2009-02-06 21:19CsimbiNote Edited: 0000224
2009-02-07 10:32Dark ByteNote Added: 0000228
2009-02-07 10:32Dark ByteStatusnew => confirmed