MULU     Multiply Unsigned     Rabbit 4000 Instruction

Opcode	Instruction	Clocks	Operation
A7	MULU	12 (2,10)	HL:BC = BC · DE (unsigned)

Flags				ALTD			IOI/IOE
S	Z	L/V	C	F	R	SP	S	D
-	-	-	-

Description

An unsigned multiplication operation is performed on the 16-bit binary integers in the BC and DE registers. The unsigned 32-bit result is loaded in HL (bits 31 through 16) and BC (bits 15 through 0).

Examples:

LD BC, 0FFFFh    ;BC gets 65,535
LD DE, 0FFFFh    ;DE gets 65,535
MULU             ;HL|BC = 4,294,836,225 HL gets 0xFFFE, BC gets 0x0001


LD BC, 0FFFFh    ;BC gets 65,535
LD DE, 00001h    ;DE gets 1
MULU             ;HL|BC = 65,535, HL gets 0x0000, BC gets 0xFFFF