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Title: Comparing two QWORDs
Post by: NoCforMe on July 12, 2022, 01:23:39 PM

Another rookie question (from a non-rookie, no less):
Is this the correct way to do an unsigned comparison between two QWORD items in regular MASM (no SSE, MMX or other fancy stuff)?

Code Select


Item1		LABEL QWORD
  Item1Hi	DD ?
  Item1Lo	DD ?

Item2		LABEL QWORD
  Item2Hi	DD ?
  Item2Lo	DD ?

;*****	Compare the two (unsigned):  *****

; Compare the high DWORDs first:
	MOV	EDX, Item1Hi
	CMP	EDX, Item2Hi
	JA	bigger
	JB	smaller

; They're equal, so compare the low DWORDs:
	MOV	EAX, Item1Lo
	CMP	EAX, Item2Lo
	JA	bigger
	JB	smaller

;*****	They're equal here ...

bigger:

smaller:

Title: Re: Comparing two QWORDs
Post by: NoCforMe on July 12, 2022, 02:27:27 PM

OK, figured it out. The answer is yes.

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