Referencing arithmetic operation as memory location

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Phirrule

Joined: 14 May 2020
Posts: 1
Location: United States

Phirrule 14 May 2020, 07:06

Is it possible to use the result of a arithmetic operation as a memory location?

For instance:

Code:

mov [bx + 4096], [bx + 32768]

In the second operand, can I perform an arithmetic operation while making it still reference a memory location. Like moving data from a memory location to another memory location while performing an offset on the register that references it.

14 May 2020, 07:06

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20303
Location: In your JS exploiting you and your system

revolution 14 May 2020, 07:18

Memory-to-memory moves are only supported with push/pop and movs

Code:

push [bx+offset] ;[bx] to [sp]
movsb ; [si] to [di]

14 May 2020, 07:18

Ali.Z

Joined: 08 Jan 2018
Posts: 716

Ali.Z 14 May 2020, 07:24

its possible, but not in the form you posted.

you will have to use string instructions such as MOVSB/MOVSW, but you will have to initialize both SI and DI registers first.

using movs? example:

Code:

lea si,[bx+8000h]
lea di,[bx+1000h]
movsb ; movsw to move WORD sized data (16-bits)

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Asm For Wise Humans

14 May 2020, 07:24

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