DESCRIPTION OF INSTRUCTIONS

76. MUL AB (Multiply accumulator by B)

 

 

7

 

 

 

 

 

 

0

 

Instruction code

:

1

0

1

0

0

1

0

0

Byte 1

Operations

: (A)0~7(A) (B)

 

 

 

 

 

 

 

 

(B)8~15

 

 

 

 

 

 

 

Number of bytes

: 1

 

 

 

 

 

 

 

 

Number of cycles

: 4

 

 

 

 

 

 

 

 

Flags

:

C

AC

F0

RS1

RS0

OV

F1

P

 

 

 

 

 

 

 

 

 

 

(PSW)

 

 

 

 

 

 

 

Description

 

 

 

 

 

 

 

 

 

 

: The accumulator contents are multiplied by the arithmetic

 

 

operation register (B) contents. The operand is always handled

 

 

as an integer without sign. The lower order byte of the result is

 

 

placed in the accumulator, and the higher order byte is placed

 

 

in the arithmetic operation register (B). The carry flag is always

 

 

cleared. The overflow flag is set to 1 if the product is greater

 

 

than 00FFH, and to 0 in all other cases.

 

 

Example MUL AB(6AH 15H=8B2H)

 

 

 

 

 

 

 

 

 

 

7

 

 

0

 

 

 

 

 

Instruction code

:

1 0

1 0

0 1

0 0

Byte 1

 

 

 

Before execution Accumulator

0 1 1 0 1 0 1 0

70 Register B

0 0 0 1 0 1 0 1

70 Overflow flag

0

After execution Accumulator

1 0 1 1 0 0 1 0

70 Register B

0 0 0 0 1 0 0 0

70 Overflow flag

1

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Sonic Alert msm83c154s, msm80154s, msm85c154hvs user manual MUL AB Multiply accumulator by B, 335