NEC 78K/0S Series User Manual page 69

SUBC
[Instruction format]
[Operation]
[Operand]
Mnemonic
SUBC A, #byte
saddr, #byte
A, r
A, saddr
[Flag]
Z AC
× ×
[Description]
•
The source operand (src) specified with the 2nd operand and the CY flag are subtracted from the destination
operand (dst) specified with the 1st operand and the result is stored in the destination operand (dst).
The CY flag is subtracted from the least significant bit. This instruction is mainly used for subtraction of two
or more bytes.
•
If the subtraction shows that dst is 0, the Z flag is set (1). In all other cases, the Z flag is cleared (0).
•
If the subtraction generates a borrow at bit 7, the CY flag is set (1). In all other cases, the CY flag is cleared
(0).
•
If the subtraction generates a borrow from bit 4 to bit 3, the AC flag is set (1). In all other cases, the AC flag
is cleared (0).
[Description example]
SUBC A, [HL]; The (HL register) address contents and the CY flag are subtracted from the A register and the
result is stored in the A register.
CHAPTER 5 EXPLANATION OF INSTRUCTIONS
SUBC dst, src
dst, CY ← dst – src – CY
Operand (dst, src)
CY
×
User's Manual U11047EJ3V0UM00
Subtraction of Byte Data with Carry
Mnemonic Operand (dst, src)
SUBC A, !addr16
A, [HL]
A, [HL + byte]
Subtract with Carry
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