Re: A83: Rotation instructions
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Re: A83: Rotation instructions
Unlike 68000 asm, the C in RLC and RRC means "Circular" rather than "Carry".
Makes more sense, doesn't it?
Linus
On 07-Aug-98, Anders Jensen wrote:
>Here is diagrams of all the shifting/rotation instructions.
>Understanding them should be simple, the instructions simply moves the
>bits in the arrows direction. Bit 0 is the least significant, bit 7 the
>most.
>RLC: (Rotate Left Carry)
> ->-->-->-->-->-->-->-
> / \
> C<-7<-6<-5<-4<-3<-2<-1<-0<-
>RL: (Rotate Left)
> ->-->-->-->-->-->-->-->-
> / \
> C<-7<-6<-5<-4<-3<-2<-1<-0<-
>RRC: (Rotate Right Carry)
> -<--<--<--<--<--<--<--
> / \
> ->7->6->5->4->3->2->1->0->C
>RR: (Rotate Right)
> -<--<--<--<--<--<--<--
> / \
> ->7->6->5->4->3->2->1->0->C
>SLA: (Shift Left Arithmetic)
> C<-7<-6<-5<-4<-3<-2<-1<-0 (bit 0 gets value 0)
>SRA: (Shift Right Arithmetic)
>7->6->5->4->3->2->1->0->C (bit 7 stays UNCHANGED)
>SRL: (Shift Right Logic)
>7->6->5->4->3->2->1->0->C (bit 7 gets value 0)
>Hope you can use it.
>Anders
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References: