NEC 78K/0 Series User Manual page 58

SUBC
[Instruction format]
[Operation]
[Operand]
Mnemonic
SUBC A, #byte
saddr, #byte
A, r
r, A
A, saddr
Note Except r = A
[Flag]
Z AC
× ×
[Description]
• The source operand (src) specified by the 2nd operand and the CY flag are subtracted from the destination
operand (dst) specified by 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 out of bit 7, the CY flag is set (1). In all other cases, the CY flag is
cleared (0).
• If the subtraction generates a borrow for bit 3 out of bit 4, 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.
58
CHAPTER 5 EXPLANATION OF INSTRUCTIONS
SUBC dst, src
dst, CY ← dst – src – CY
Operand(dst,src)
Note
CY
×
User's Manual U12326EJ4V0UM
Subtraction of Byte Data with Carry
Mnemonic Operand(dst,src)
SUBC A, !addr16
A, [HL]
A, [HL+byte]
A, [HL+B]
A, [HL+C]
Subtract with Carry