DESCRIPTION OF INSTRUCTIONS

97. SUBB A, #data (Substract immediate data from accumulator with borrow)

 

 

 

7

 

 

 

 

 

 

 

 

 

 

0

 

 

Instruction code

:

 

1

 

0

 

 

0

 

1

0

1

0

0

 

Byte 1

 

 

 

7

 

 

 

 

 

 

 

 

 

 

0

 

 

#data

 

 

I7

 

I6

 

I5

 

I4

I3

I2

I1

I0

 

Byte 2

Operation

: (A)(A)–((C)+#data)

 

 

 

 

 

 

Number of bytes

: 2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Number of cycles

: 1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Flags

:

 

C

AC

F0

RS1

RS0

OV

F1

P

 

(PSW)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Description

: The carry flag content and an immediate data value are

 

 

substracted from the accumulator contents. The result is placed

 

 

in the accumulator, and the flags are updated.

 

Example SUBB A, #05H

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

7

 

 

 

 

 

 

 

0

 

 

 

 

 

 

Instruction code

:

1

0

0

1

 

0

1

0

0

Byte 1

 

 

 

 

 

7

 

 

 

 

 

 

 

0

 

 

 

 

 

 

 

 

0

0

0

0

 

0

1

0

1

Byte 2

 

 

 

 

Before execution Carry flag

1

Auxiliary carry flag

0

Overflow flag

1

Accumulator

1 0 1 0 1 0 0 1

70

After execution Carry flag

0

Auxiliary carry flag

0

Overflow flag

0

Accumulator

1 0 1 0 0 0 1 1

70

357

Page 364
Image 364
Sonic Alert msm80154s, msm83c154s, msm85c154hvs user manual 357, RS1