I am unsure of what the cbw command actually does. I have a snippet of code:
mov ax,0FF0h
cbw
idiv ah
How does the value of ax change after cbw?
I am unsure of what the cbw command actually does. I have a snippet
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I am unsure of what the cbw command actually does. I have a snippet of code:
mov ax,0FF0h
cbw
idiv ah
How does the value of ax change after cbw?
The
cbwinstruction sign-extends a byte into a word. In this case, it’ll take the sign bit ofAL(which happens to be 1) and copy it into every bit ofAH.This means that the two’s-complement value of
AXwill be the same, but the binary representation will be different.The value of
AXafter thecbwinstruction will beFFF0h(a 16-bit -16 value, just likeALwas originally an 8-bit -16)