NEC 78K/0 Series SUBC

58

CHAPTER 5 EXPLANATION OF INSTRUCTIONS

User's Manual U12326EJ4V0UM

Subtract with Carry

SUBC Subtraction of Byte Data with Carry

[Instruction format] SUBC dst, src

[Operation] dst, CY ← dst – src – CY

[Operand]

Mnemonic Operand(dst,src) Mnemonic Operand(dst,src)

SUBC A, #byte SUBC A, !addr16

saddr, #byte A, [HL]

A, r Note A, [HL+byte]

r, A A, [HL+B]

A, saddr A, [HL+C]

Note Except r = A

[Flag]

ZACCY

×××

[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.

Contents

Main Page IEBus is a trademark of NEC Corporation. NOTES FOR CMOS DEVICES 4 Regional Information NEC Electronics Hong Kong Ltd. Device availability Ordering information Product release schedule Page INTRODUCTION Page Page Page Page Page 1.7 Special Function Register (SFR) Area 1.8 External Memory Space 1.9 IEBusTM Register Area 14 CHAPTER 2 REGISTERS 2.1 Control Registers Page Figure 2-5. Data to Be Reset from Stack Memory 2.2 General-Purpose Registers CHAPTER 2 REGISTERS Figure 2-6. General-Purpose Register Configuration (a) Absolute names (b) Functional names 2.3 Special Function Registers (SFRs) 20 CHAPTER 3 ADDRESSING 3.1 Instruction Address Addressing Page Page Page 3.2 Operand Address Addressing Page Page Page Page Page Page Page 32 CHAPTER 4 INSTRUCTION SET 4.1 Operation Page Page CHAPTER 4 INSTRUCTION SET Note Except r = A. CHAPTER 4 INSTRUCTION SET Note Only when rp = BC, DE or HL. (2) 16-bit instructions MOVW, XCHW, ADDW, SUBW, CMPW, PUSH, POP, INCW, DECW (3) Bit manipulation instructions MOV1, AND1, OR1, XOR1, SET1, CLR1, NOT1, BT, BF, BTCLR Page 4.2 Instruction Codes 4.2.2 Instruction code list Notes 1. Only when rp = BC, DE or HL. 2. Except r = A. Page Page Page Page Page Page Page Page MOV XCH Page MOVW XCHW Page ADD ADDC SUB SUBC AND OR XOR CMP Page ADDW SUBW CMPW Page MULU DIVUW Page INC DEC INCW DECW Page ROR ROL RORC ROLC ROR4 ROL4 Page ADJBA ADJBS Page MOV1 AND1 OR1 XOR1 SET1 CLR1 NOT1 Page CALL CALLF CALLT BRK RET RETI RETB Page PUSH POP MOVW SP , src MOVW AX, SP Page BR Page BC BNC BZ BNZ BT BF BTCLR DBNZ Page SEL RBn NOP EI DI HALT STOP APPENDIX A REVISION HISTORY 124 APPENDIX B INSTRUCTION INDEX (MNEMONIC: BY FUNCTION) Page 126 APPENDIX C INSTRUCTION INDEX (MNEMONIC: IN ALPHABETICAL ORDER) Page Page Facsimile Message Thank you for your kind support. From: