Emma 02

This page describes the additional instructions of the CDP1805 which is the successor of the CDP1804.

xx	8 bit value
xxxx	16 bit value
RN	Register number N (N = 0 to F), RN can also be represented as N in all commands
RX	Stack or data pointer register
RP	Program counter register
RN.0, RX.0 or RP.0	Lower order byte or RN, RX or RP
RN.1, RX.1 or RP.1	Higher order byte or RN, RX or RP
M(RN)->D; RN+1->RN	This notation means: The memory byte pointed to by RN is loaded into D, and RN is incremented by 1.

Instruction	Mnemonic	Opcode	Definition
REGISTER OPERATIONS
DECREMENT REG N AND LONG BRANCH IF NOT EQUAL 0	DBNZ R1, xxxx	682N	RN-1->RN; IF RN NOT 0, M(RP)->RP.1, M(RP+1)->RP.0, ELSE RP+2->RP
ARITHMETIC OPERATIONS
DECIMAL ADD	DADD	68F4	M(RX)+D->DF, D; DECIMAL ADJUST->DF, D
DECIMAL ADD IMMEDIATE	DADI xx	68FC	M(RP)+D->DF, D; RP+1->RP; DECIMAL ADJUST->DF, D
DECIMAL ADD WITH CARRY	DADC	6874	M(RX)+D+DF->DF, D; DECIMAL ADJUST->DF, D
DECIMAL ADD WITH CARRY IMMEDIATE	DACI xx	687C	M(RP)+D+DF->DF, D; RP+1->RP; DECIMAL ADJUST->DF, D
DECIMAL SUBTRACT MEMORY	DSM	68F7	D-M(RX)->DF, D; DECIMAL ADJUST->DF, D
DECIMAL SUBTRACT MEMORY IMMEDIATE	DSMI xx	68FF	D-M(RP)->DF, D; RP+1->RP; DECIMAL ADJUST->DF, D
DECIMAL SUBTRACT MEMORY WITH BORROW	DSMB	6877	D-M(RX)-(NOT DF)->DF, D; DECIMAL ADJUST->DF, D
DECIMAL SUBTRACT WITH BORROW IMMEDIATE	DSBI xx	687F	D-M(RP)-(NOT DF)->DF, D; RP+1->RP; DECIMAL ADJUST->DF, D
INTERRUPT CONTROL
SAVE T, D, DF	DSAV	6876	RX-1->RX; T->M(RX); RX-1->RX; D->M(RX); RX-1->RX; SHIFT D RIGHT WITH CARRY; D->M(RX)

EMMA 02