Intel 8XC251SA, User Manual

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8XC251SA, SB, SP, SQ USER’S MANUAL
A-102
MUL WRjd,WRjs
Binary Mode Source Mode
Bytes: 3 2
States: 12 11
Hex Code in: Binary Mode = [A5][Encoding]
Source Mode = [Encoding]
Operation: MUL (16-bit operands)
if <dest> jd = 0, 4, 8, .., 28
WRjd
←
high word of the WRjd X WRjs
WRjd+2
←
low word of the WRjd X WRjs
if <dest> jd = 2, 6, 10, .., 30
WRjd–2
←
high word of the WRjd X WRjs
WRjd
←
low word of the WRjd X WRjs
MUL AB
Function: Multiply
Description: Multiplies the unsigned 8-bit integers in the accumulator and register B. The low byte of the
16-bit product is left in the accumulator, and the high byte is left in register B. If the product is
greater than 255 (0FFH) the OV flag is set; otherwise it is clear. The CY flag is always clear.
Flags:
Example: The accumulator contains 80 (50H) and register B contains 160 (0A0H). After executing the
instruction
MUL AB
which gives the product 12,800 (3200H), register B contains 32H (00110010B), the
accumulator contains 00H, the OV flag is set, and the CY flag is clear.
Binary Mode Source Mode
Bytes: 1 1
States: 5 5
Hex Code in: Binary Mode = [Encoding]
Source Mode = [Encoding]
Operation: MUL
(A)
←
low byte of (A) X (B)
(B)
←
high byte of (A) X (B)
[Encoding] 1 0 1 0 1 1 0 1 t t t t t t t t
CY AC OV N Z
0 —
✓ ✓ ✓
[Encoding] 1 0 1 0 0 1 0 0