DR805X Datasheet, PDF (57/79 Pages) Digital Core Design – 8-bit RISC Microcontroller Instructions set details ver 3.10

DR805x Instructions set details
3.27. MUL
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Instruction: MUL AB
Function: Multiply
Description:
MUL AB multiplies the unsigned eight-bit integers in the accumulator
and register B. The low-order byte of the sixteen-bit product is left in the
accumulator, and the high-order byte in B. If the product is greater than
255 (0FF H) the overflow flag is set; otherwise it is cleared. The carry
flag is always cleared.
Operation:
(PC) ← (PC) + 1
(A) ← (A) x (B) – result’s bits 7..0
(B) ← (A) x (B) – result’s bits 15..8
Bytes:
Cycles:
Encoding:
1
4
10100100
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