Toshiba 6F3B0253 user manual FUN Subtraction with carry

6F3B0253

7. Instructions

FUN 036

-C

Subtraction with carry

Expression

Input − [ A -C B → C ]− Output

Function

When the input is ON, the data of B and the carry flag (CF = S050) are subtracted from A, and the result is stored in C. If borrow is occurred in the operation, the carry flag is set to ON. If the result is greater than 32767 or smaller than -32768, the output is turned ON.

This instruction is used to perform unsigned subtraction or double-length subtraction.

Execution condition

Input		Operation		Output	CF
OFF	No execution			OFF	−
ON	Execution	Normal	No borrow	OFF	Reset
			Borrow occurred	OFF	Set
		Overflow /	No borrow	ON	Reset
		underflow	Borrow occurred	ON	Set

Operand

Name

Device

Register

Constant

Index

X

Y

R

S

T.

C.

XW

YW

RW

SW

T

C

D

I

J

K

A

Minuend

√

√

√

√

√

√

√

√

√

√

√

√

B

Subtrahend

√

√

√

√

√

√

√

√

√

√

√

√

C

Difference

√

√

√

√

√

√

√

√

√

√

Example

When R013 is ON, the data of double-length register RW23⋅RW22 is subtracted from the data of D0201⋅D0200, and the result is stored in D0211⋅D0210. The RSTC is a instruction to reset the carry flag before starting the calculation.

If the data of D0201⋅D0200 is 12345678 and RW23⋅RW22 is 12340000, the result 5678 is stored in D0211⋅D0210.

D0201⋅D0200

RW23⋅RW22

12345678

- D0211⋅D0210

12340000

5678

150 T1-16S User’s Manual