Data Transfer Group:
The data transfer instructions move data between registers or between memory and registers.
MOV Move
MVI Move Immediate
LDA Load Accumulator Directly from Memory
STA Store Accumulator Directly in Memory
LHLD Load H & L Registers Directly from Memory
SHLD Store H & L Registers Directly in Memory
An 'X' in the name of a data transfer instruction implies that it deals with a register pair (16-bits);
LXI Load Register Pair with Immediate data
LDAX Load Accumulator from Address in Register Pair
STAX Store Accumulator in Address in Register Pair
XCHG Exchange H & L with D & E
XTHL Exchange Top of Stack with H & L
Arithmetic Group:
The arithmetic instructions add, subtract, increment, or decrement data in registers or memory.
ADD Add to Accumulator
ADI Add Immediate Data to Accumulator
ADC Add to Accumulator Using Carry Flag
ACI Add Immediate data to Accumulator Using Carry
SUB Subtract from Accumulator
SUI Subtract Immediate Data from Accumulator
SBB Subtract from Accumulator Using Borrow (Carry) Flag
SBI Subtract Immediate from Accumulator Using Borrow (Carry) Flag
INR Increment Specified Byte by One
DCR Decrement Specified Byte by One
INX Increment Register Pair by One
DCX Decrement Register Pair by One
DAD Double Register Add; Add Content of Register
Pair to H & L Register Pair
Logical Group:
This group performs logical (Boolean) operations on data in registers and memory and on condition flags.
The logical AND, OR, and Exclusive OR instructions enable you to set specific bits in the accumulator ON or OFF.
ANA Logical AND with Accumulator
ANI Logical AND with Accumulator Using Immediate Data
ORA Logical OR with Accumulator
OR Logical OR with Accumulator Using Immediate Data
XRA Exclusive Logical OR with Accumulator
XRI Exclusive OR Using Immediate Data
The Compare instructions compare the content of an 8-bit value with the contents of the accumulator;
CMP Compare
CPI Compare Using Immediate Data
The rotate instructions shift the contents of the accumulator one bit position to the left or right:
RLC Rotate Accumulator Left
RRC Rotate Accumulator Right
RAL Rotate Left Through Carry
RAR Rotate Right Through Carry
Complement and carry flag instructions:
CMA Complement Accumulator
CMC Complement Carry Flag
STC Set Carry Flag
Branch Group:
The branching instructions alter normal sequential program flow, either unconditionally or conditionally. The unconditional branching instructions are as follows:
JMP Jump
CALL Call
RET Return
Conditional branching instructions examine the status of one of four condition flags to determine whether the specified branch is to be executed. The conditions that may be specified are as follows:
NZ Not Zero (Z = 0)
Z Zero (Z = 1)
NC No Carry (C = 0)
C Carry (C = 1)
PO Parity Odd (P = 0)
PE Parity Even (P = 1)
P Plus (S = 0)
M Minus (S = 1)
Thus, the conditional branching instructions are specified as follows:
Jumps Calls Returns
C CC RC (Carry)
INC CNC RNC (No Carry)
JZ CZ RZ (Zero)
JNZ CNZ RNZ (Not Zero)
JP CP RP (Plus)
JM CM RM (Minus)
JPE CPE RPE (Parity Even)
JP0 CPO RPO (Parity Odd)
Two other instructions can affect a branch by replacing the contents or the program counter:
PCHL Move H & L to Program Counter
RST Special Restart Instruction Used
with Interrupts
Stack I/O, and Machine Control Instructions:
The following instructions affect the Stack and/or Stack Pointer:
PUSH Push Two bytes of Data onto the Stack
POP Pop Two Bytes of Data off the Stack
XTHL Exchange Top of Stack with H & L
SPHL Move content of H & L to Stack Pointer
The I/0 instructions are as follows:
IN Initiate Input Operation
OUT Initiate Output Operation
The Machine Control instructions are as follows:
EI Enable Interrupt System
DI Disable Interrupt System
HLT Halt
NOP No Operation
----------------------------------------------------------------
|Mnemonic |Op|SZAPC|~s|Description |Notes |
|---------+--+-----+--+--------------------------+-------------|
|ACI n |CE|*****| 7|Add with Carry Immediate |A=A+n+CY |
|ADC r |8F|*****| 4|Add with Carry |A=A+r+CY(21X)|
|ADC M |8E|*****| 7|Add with Carry to Memory |A=A+[HL]+CY |
|ADD r |87|*****| 4|Add |A=A+r (20X)|
|ADD M |86|*****| 7|Add to Memory |A=A+[HL] |
|ADI n |C6|*****| 7|Add Immediate |A=A+n |
|ANA r |A7|****0| 4|AND Accumulator |A=A&r (24X)|
|ANA M |A6|****0| 7|AND Accumulator and Memory|A=A&[HL] |
|ANI n |E6|**0*0| 7|AND Immediate |A=A&n |
|CALL a |CD|-----|18|Call unconditional |-[SP]=PC,PC=a|
|CC a |DC|-----| 9|Call on Carry |If CY=1(18~s)|
|CM a |FC|-----| 9|Call on Minus |If S=1 (18~s)|
|CMA |2F|-----| 4|Complement Accumulator |A=~A |
|CMC |3F|----*| 4|Complement Carry |CY=~CY |
|CMP r |BF|*****| 4|Compare |A-r (27X)|
|CMP M |BF|*****| 7|Compare with Memory |A-[HL] |
|CNC a |D4|-----| 9|Call on No Carry |If CY=0(18~s)|
|CNZ a |C4|-----| 9|Call on No Zero |If Z=0 (18~s)|
|CP a |F4|-----| 9|Call on Plus |If S=0 (18~s)|
|CPE a |EC|-----| 9|Call on Parity Even |If P=1 (18~s)|
|CPI n |FE|*****| 7|Compare Immediate |A-n |
|CPO a |E4|-----| 9|Call on Parity Odd |If P=0 (18~s)|
|CZ a |CC|-----| 9|Call on Zero |If Z=1 (18~s)|
|DAA |27|*****| 4|Decimal Adjust Accumulator|A=BCD format |
|DAD B |09|----*|10|Double Add BC to HL |HL=HL+BC |
|DAD D |19|----*|10|Double Add DE to HL |HL=HL+DE |
|DAD H |29|----*|10|Double Add HL to HL |HL=HL+HL |
|DAD SP |39|----*|10|Double Add SP to HL |HL=HL+SP |
|DCR r |3D|****-| 4|Decrement |r=r-1 (0X5)|
|DCR M |35|****-|10|Decrement Memory |[HL]=[HL]-1 |
|DCX B |0B|-----| 6|Decrement BC |BC=BC-1 |
|DCX D |1B|-----| 6|Decrement DE |DE=DE-1 |
|DCX H |2B|-----| 6|Decrement HL |HL=HL-1 |
|DCX SP |3B|-----| 6|Decrement Stack Pointer |SP=SP-1 |
|DI |F3|-----| 4|Disable Interrupts | |
|EI |FB|-----| 4|Enable Interrupts | |
|HLT |76|-----| 5|Halt | |
|IN p |DB|-----|10|Input |A=[p] |
|INR r |3C|****-| 4|Increment |r=r+1 (0X4)|
|INR M |3C|****-|10|Increment Memory |[HL]=[HL]+1 |
|INX B |03|-----| 6|Increment BC |BC=BC+1 |
|INX D |13|-----| 6|Increment DE |DE=DE+1 |
|INX H |23|-----| 6|Increment HL |HL=HL+1 |
|INX SP |33|-----| 6|Increment Stack Pointer |SP=SP+1 |
|JMP a |C3|-----| 7|Jump unconditional |PC=a |
|JC a |DA|-----| 7|Jump on Carry |If CY=1(10~s)|
|JM a |FA|-----| 7|Jump on Minus |If S=1 (10~s)|
|JNC a |D2|-----| 7|Jump on No Carry |If CY=0(10~s)|
|JNZ a |C2|-----| 7|Jump on No Zero |If Z=0 (10~s)|
|JP a |F2|-----| 7|Jump on Plus |If S=0 (10~s)|
|JPE a |EA|-----| 7|Jump on Parity Even |If P=1 (10~s)|
|JPO a |E2|-----| 7|Jump on Parity Odd |If P=0 (10~s)|
|JZ a |CA|-----| 7|Jump on Zero |If Z=1 (10~s)|
|LDA a |3A|-----|13|Load Accumulator direct |A=[a] |
|LDAX B |0A|-----| 7|Load Accumulator indirect |A=[BC] |
|LDAX D |1A|-----| 7|Load Accumulator indirect |A=[DE] |
|LHLD a |2A|-----|16|Load HL Direct |HL=[a] |
|LXI B,nn |01|-----|10|Load Immediate BC |BC=nn |
|LXI D,nn |11|-----|10|Load Immediate DE |DE=nn |
|LXI H,nn |21|-----|10|Load Immediate HL |HL=nn |
|LXI SP,nn|31|-----|10|Load Immediate Stack Ptr |SP=nn |
|MOV r1,r2|7F|-----| 4|Move register to register |r1=r2 (1XX)|
|MOV M,r |77|-----| 7|Move register to Memory |[HL]=r (16X)|
|MOV r,M |7E|-----| 7|Move Memory to register |r=[HL] (1X6)|
|MVI r,n |3E|-----| 7|Move Immediate |r=n (0X6)|
|MVI M,n |36|-----|10|Move Immediate to Memory |[HL]=n |
|NOP |00|-----| 4|No Operation | |
|ORA r |B7|**0*0| 4|Inclusive OR Accumulator |A=Avr (26X)|
|ORA M |B6|**0*0| 7|Inclusive OR Accumulator |A=Av[HL] |
|ORI n |F6|**0*0| 7|Inclusive OR Immediate |A=Avn |
|OUT p |D3|-----|10|Output |[p]=A |
|PCHL |E9|-----| 6|Jump HL indirect |PC=[HL] |
|POP B |C1|-----|10|Pop BC |BC=[SP]+ |
|POP D |D1|-----|10|Pop DE |DE=[SP]+ |
|POP H |E1|-----|10|Pop HL |HL=[SP]+ |
|POP PSW |F1|-----|10|Pop Processor Status Word |{PSW,A}=[SP]+|
----------------------------------------------------------------
----------------------------------------------------------------
|Mnemonic |Op|SZAPC|~s|Description |Notes |
|---------+--+-----+--+--------------------------+-------------|
|PUSH B |C5|-----|12|Push BC |-[SP]=BC |
|PUSH D |D5|-----|12|Push DE |-[SP]=DE |
|PUSH H |E5|-----|12|Push HL |-[SP]=HL |
|PUSH PSW |F5|-----|12|Push Processor Status Word|-[SP]={PSW,A}|
|RAL |17|----*| 4|Rotate Accumulator Left |A={CY,A}<- |
|RAR |1F|----*| 4|Rotate Accumulator Righ |A=->{CY,A} |
|RET |C9|-----|10|Return |PC=[SP]+ |
|RC |D8|-----| 6|Return on Carry |If CY=1(12~s)|
|RIM |20|-----| 4|Read Interrupt Mask |A=mask |
|RM |F8|-----| 6|Return on Minus |If S=1 (12~s)|
|RNC |D0|-----| 6|Return on No Carry |If CY=0(12~s)|
|RNZ |C0|-----| 6|Return on No Zero |If Z=0 (12~s)|
|RP |F0|-----| 6|Return on Plus |If S=0 (12~s)|
|RPE |E8|-----| 6|Return on Parity Even |If P=1 (12~s)|
|RPO |E0|-----| 6|Return on Parity Odd |If P=0 (12~s)|
|RZ |C8|-----| 6|Return on Zero |If Z=1 (12~s)|
|RLC |07|----*| 4|Rotate Left Circular |A=A<- |
|RRC |0F|----*| 4|Rotate Right Circular |A=->A |
|RST z |C7|-----|12|Restart (3X7)|-[SP]=PC,PC=z|
|SBB r |9F|*****| 4|Subtract with Borrow |A=A-r-CY |
|SBB M |9E|*****| 7|Subtract with Borrow |A=A-[HL]-CY |
|SBI n |DE|*****| 7|Subtract with Borrow Immed|A=A-n-CY |
|SHLD a |22|-----|16|Store HL Direct |[a]=HL |
|SIM |30|-----| 4|Set Interrupt Mask |mask=A |
|SPHL |F9|-----| 6|Move HL to SP |SP=HL |
|STA a |32|-----|13|Store Accumulator |[a]=A |
|STAX B |02|-----| 7|Store Accumulator indirect|[BC]=A |
|STAX D |12|-----| 7|Store Accumulator indirect|[DE]=A |
|STC |37|----1| 4|Set Carry |CY=1 |
|SUB r |97|*****| 4|Subtract |A=A-r (22X)|
|SUB M |96|*****| 7|Subtract Memory |A=A-[HL] |
|SUI n |D6|*****| 7|Subtract Immediate |A=A-n |
|XCHG |EB|-----| 4|Exchange HL with DE |HL<->DE |
|XRA r |AF|**0*0| 4|Exclusive OR Accumulator |A=Axr (25X)|
|XRA M |AE|**0*0| 7|Exclusive OR Accumulator |A=Ax[HL] |
|XRI n |EE|**0*0| 7|Exclusive OR Immediate |A=Axn |
|XTHL |E3|-----|16|Exchange stack Top with HL|[SP]<->HL |
|------------+-----+--+----------------------------------------|
| PSW |-*01 | |Flag unaffected/affected/reset/set |
| S |S | |Sign (Bit 7) |
| Z | Z | |Zero (Bit 6) |
| AC | A | |Auxilary Carry (Bit 4) |
| P | P | |Parity (Bit 2) |
| CY | C| |Carry (Bit 0) |
|---------------------+----------------------------------------|
| a p |Direct addressing |
| M z |Register indirect addressing |
| n nn |Immediate addressing |
| r |Register addressing |
|---------------------+----------------------------------------|
|DB n(,n) |Define Byte(s) |
|DB 'string' |Define Byte ASCII character string |
|DS nn |Define Storage Block |
|DW nn(,nn) |Define Word(s) |
|---------------------+----------------------------------------|
| A B C D E H L |Registers (8-bit) |
| BC DE HL |Register pairs (16-bit) |
| PC |Program Counter register (16-bit) |
| PSW |Processor Status Word (8-bit) |
| SP |Stack Pointer register (16-bit) |
|---------------------+----------------------------------------|
| a nn |16-bit address/data (0 to 65535) |
| n p |8-bit data/port (0 to 255) |
| r |Register (X=B,C,D,E,H,L,M,A) |
| z |Vector (X=0H,8H,10H,18H,20H,28H,30H,38H)|
|---------------------+----------------------------------------|
| + - |Arithmetic addition/subtraction |
| & ~ |Logical AND/NOT |
| v x |Logical inclusive/exclusive OR |
| <- -> |Rotate left/right |
| <-> |Exchange |
| [ ] |Indirect addressing |
| [ ]+ -[ ] |Indirect address auto-inc/decrement |
| { } |Combination operands |
| ( X ) |Octal op code where X is a 3-bit code |
| If ( ~s) |Number of cycles if condition true |
----------------------------------------------------------------
