;  December 18, 1986
;  MS-DOS compatible Source code for MCS BASIC-52 (tm) 
;  Assembles with ASM51 Macro Assembler Version 2.2
;
;  The following source code does not include the floating point math
;  routines. These are seperately compiled using FP52.SRC.
;
;  Both the BASIC.SRC and FP52.SRC programs assemble into ABSOLUTE 
;  object files, and do not need to be relocated or linked. The FP52 
;  object code and the BASIC object code, when compiled without modification
;  of the source listings, create the same object code that is found on
;  the MCS BASIC-52 Version 1.1 microcontrollers.
;
;  The original source code had 7 "include" files that have been incorporated
;  into this file for ease of assembly. 
;  These 7 files are: LOOK52.SRC, BAS52.RST, BAS52.PGM, BAS52.TL, BAS52.OUT,
;  BAS52.PWM, and BAS52.CLK.
;
;
;                       Intel Corporation, Embedded Controller Operations

$EJECT
	;**************************************************************
	;
	; TRAP VECTORS TO MONITOR
	;
	; RESET TAG (0AAH) ---------2001H
	;
	; TAG LOCATION (5AH) ------ 2002H
	;
	; EXTERNAL INTERRUPT 0 ---- 2040H
	;
	; COMMAND MODE ENTRY ------ 2048H
	;
	; SERIAL PORT ------------- 2050H
	;
	; MONITOR (BUBBLE) OUTPUT - 2058H
	;
	; MONITOR (BUBBLE) INPUT -- 2060H
	;
	; MONITOR (BUBBLE) CSTS --- 2068H
	;
	; GET USER JUMP VECTOR ---- 2070H
	;
	; GET USER LOOKUP VECTOR -- 2078H
	;
	; PRINT AT VECTOR --------- 2080H
	;
	; INTERRUPT PWM ----------- 2088H
	;
	; EXTERNAL RESET ---------- 2090H
	;
	; USER OUTPUT-------------- 4030H
	;
	; USER INPUT -------------- 4033H
	;
	; USER CSTS --------------- 4036H
	;
	; USER RESET -------------- 4039H
	;
	; USER DEFINED PRINT @ ---  403CH
	;
	;***************************************************************
	;
$EJECT
	;***************************************************************
	;
	; MCS - 51  -  8K BASIC VERSION 1.1
	;
	;***************************************************************
	;
	AJMP	CRST		;START THE PROGRAM
	;
	ORG	3H
	;
	;***************************************************************
	;
	;EXTERNAL INTERRUPT 0
	;
	;***************************************************************
	;
	JB	DRQ,STQ		;SEE IF DMA IS SET
	PUSH	PSW		;SAVE THE STATUS
	LJMP	4003H		;JUMP TO USER IF NOT SET
	;
	ORG	0BH
	;
	;***************************************************************
	;
	;TIMER 0 OVERFLOW INTERRUPT
	;
	;***************************************************************
	;
	PUSH	PSW		;SAVE THE STATUS
	JB	C_BIT,STJ	;SEE IF USER WANTS INTERRUPT
	LJMP	400BH		;EXIT IF USER WANTS INTERRUPTS
	;
	ORG	13H
	;
	;***************************************************************
	;
	;EXTERNAL INTERRUPT 1
	;
	;***************************************************************
	;
	JB	INTBIT,STK
	PUSH	PSW
	LJMP	4013H
	;
$EJECT
	;
	ORG	1BH
	;
	;***************************************************************
	;
	;TIMER 1 OVERFLOW INTERRUPT
	;
	;***************************************************************
	;
	PUSH	PSW
	LJMP	CKS_I
	;
STJ:	LJMP	I_DR		;DO THE INTERRUPT
	;
	;***************************************************************
	;
	;SERIAL PORT INTERRUPT
	;
	;***************************************************************
	;
	ORG	23H
	;
	PUSH	PSW
	JB	SPINT,STU	;SEE IF MONITOR EANTS INTERRUPT
	LJMP	4023H
	;
	ORG	2BH
	;
	;**************************************************************
	;
	;TIMER 2 OVERFLOW INTERRUPT
	;
	;**************************************************************
	;
	PUSH	PSW
	LJMP	402BH
	;
$EJECT
	;**************************************************************
	;
	;USER ENTRY
	;
	;**************************************************************
	;
	ORG	30H
	;
	LJMP	IBLK		;LINK TO USER BLOCK
	;
STQ:	JB	I_T0,STS	;SEE IF MONITOR WANTS IT
	CLR	DACK
	JNB	P3.2,$		;WAIT FOR DMA TO END
	SETB	DACK
	RETI
	;
STS:	LJMP	2040H		;GO TO THE MONITOR
	;
STK:	SETB	INTPEN		;TELL BASIC AN INTERRUPT WAS RECEIVED
	RETI
	;
STU:	LJMP	2050H		;SERIAL PORT INTERRUPT
	;
$EJECT

;$INCLUDE(:F2:LOOK52.SRC)
; INCLUDED BELOW

	;
	;**************************************************************
	;
	; This is the equate table for 8052 basic.
	;
	;**************************************************************
	;
	; The register to direct equates for CJNE instructions.
	;
R0B0	EQU	0
R1B0	EQU	1
R2B0	EQU	2
R3B0	EQU	3
R4B0	EQU	4
R5B0	EQU	5
R6B0	EQU	6
R7B0	EQU	7
	;
	; Register bank 1 contains the text pointer
	; and the arg stack pointer.
	;
TXAL	EQU	8		;R0 BANK 1 = TEXT POINTER LOW
ASTKA	EQU	9		;R1 BANK 1 = ARG STACK
TXAH	EQU	10		;R2 BANK 1 = TEXT POINTER HIGH
	;
	; Now five temporary locations that are used by basic.
	;
TEMP1	EQU	11
TEMP2	EQU	12
TEMP3	EQU	13
TEMP4	EQU	14
TEMP5	EQU	15
	;
$EJECT
	; Register bank 2 contains the read text pointer
	; and the control stack pointer.
	;
RTXAL	EQU	16		;R0 BANK 2 = READ TEXT POINTER LOW
CSTKA	EQU	17		;R1 BANK 2 = CONTROL STACK POINTER
RTXAH	EQU	18		;R2 BANK 2 = READ TEXT POINTER HIGH
	;
	; Now some internal system equates.
	;
BOFAH	EQU	19		;START OF THE BASIC PROGRAM, HIGH BYTE
BOFAL	EQU	20		;START OF THE BASIC PROGRAM, LOW BYTE
NULLCT	EQU	21		;NULL COUNT
PHEAD	EQU	22		;PRINT HEAD POSITION
FORMAT	EQU	23
	;
	; Register bank 3 is for the user and can be loaded
	; by basic
	;
	;
	;
	; Now everything else is used by basic.
	; First the bit locations, these use bytes 34, 35, 36, 37 and 38
	;
$EJECT
OTS		BIT	16	;34.0-ON TIME INSTRUCTION EXECUTED
INPROG		BIT	17	;34.1-INTERRUPT IN PROCESS
INTBIT		BIT	18	;34.2-INTERRUPT SET BIT
ON_ERR		BIT	19	;34.3-ON ERROR EXECUTED
OTI		BIT	20	;34.4-ON TIME INTERRUPT IN PROGRESS
LINEB		BIT	21	;34.5-LINE CHANGE OCCURED
INTPEN		BIT	22	;34.6-INTERRUPT PENDING BIT
CONB		BIT	23	;34.7-CAN CONTINUE IF SET
GTRD		BIT	24	;35.0-READ GET LOCATION
LPB		BIT	25	;35.1-PRINT TO LINE PRINTER PORT
CKS_B		BIT	26	;35.2-FOR PWM INTERRUPT
COB		BIT	27	;35.3-CONSOLE OUT BIT
				;     0 = SERIAL PORT
				;     1 = LINE PRINTER
COUB		BIT	28	;35.4-USER CONSOLE OUT BIT
				;     0 = SERIAL PORT
				;     1 = USER DRIVER
INBIT		BIT	29	;35.5-INITIALIZATION BIT
CIUB		BIT	30	;35.6-USER CONSOLE IN BIT
				;     0 = SERIAL PORT
				;     1 = USER ROUTINE
SPINT		BIT	31	;35.7-SERIAL PORT INTERRUPT
STOPBIT		BIT	32	;36.0-PROGRAM STOP ENCOUNTERED
U_IDL		BIT	33	;36.1-USER IDLE BREAK
INP_B		BIT	34	;36.2-SET DURING INPUT INSTRUCTION
;DCMPXZ		BIT	35	;36.3-DCMPX ZERO FLAG
ARGF		BIT	36	;36.4-ARG STACK HAS A VALUE
RETBIT		BIT	37	;36.5-RET FROM INTERRUPT EXECUTED
I_T0		BIT	38	;36.6-TRAP INTERRUPT ZERO TO MON
UPB		BIT	39	;36.7-SET WHEN @ IS VALID
JKBIT		BIT	40	;37.0-WB TRIGGER
ENDBIT		BIT	41	;37.1-GET END OF PROGRAM
UBIT		BIT	42	;37.2-FOR DIM STATEMENT
ISAV		BIT	43	;37.3-SAVE INTERRUPT STATUS
BO		BIT	44	;37.4-BUBBLE OUTPUT
XBIT		BIT	45	;37.5-EXTERNAL PROGRAM PRESENT
C_BIT		BIT	46	;37.6-SET WHEN CLOCK RUNNING
DIRF		BIT	47	;37.7-DIRECT INPUT MODE
NO_C		BIT	48	;38.0-NO CONTROL C
DRQ		BIT	49	;38.1-DMA ENABLED
BI		BIT	50	;38.2-BUBBLE INPUT
INTELB		BIT	51	;38.3-INTELLIGENT PROM PROGRAMMING
C0ORX1		BIT	52	;38.4-PRINT FROM ROM OR RAM
CNT_S		BIT	53	;38.5-CONTROL S ENCOUNTERED
ZSURP		BIT	54	;38.6-ZERO SUPRESS
HMODE		BIT	55	;38.7-HEX MODE PRINT
LP		BIT	P1.7	;SOFTWARE LINE PRINTER
DACK		BIT	P1.6	;DMA ACK
PROMV		BIT	P1.5	;TURN ON PROM VOLTAGE
PROMP		BIT	P1.4	;PROM PULSE
ALED		BIT	P1.3	;ALE DISABLE
T_BIT		BIT	P1.2	;I/O TOGGLE BIT
	;
$EJECT
	;
	; The next location is a bit addressable byte counter
	;
BABC	EQU	39
	;
	; Now floating point and the other temps
	;
	; FP Uses to locations 03CH
	;
	; Now the stack designators.
	;
SPSAV	EQU	3EH
S_LEN	EQU	3FH
T_HH	EQU	40H
T_LL	EQU	41H
INTXAH	EQU	42H
INTXAL	EQU	43H
MT1	EQU	45H
MT2	EQU	46H
MILLIV	EQU	47H		;TIMER LOCATIONS
TVH	EQU	48H
TVL	EQU	49H
SAVE_T	EQU	4AH
SP_H	EQU	4BH		;SERIAL PORT TIME OUT
SP_L	EQU	4CH
CMNDSP	EQU	4DH		;SYSTEM STACK POINTER
IRAMTOP	EQU	0FFH		;TOP OF RAM
STACKTP	EQU	0FEH		;ARG AND CONTROL STACK TOPS
	;
	; The character equates
	;
CR	EQU	0DH		;CARRIAGE RETURN
LF	EQU	0AH		;LINE FEED
BELL	EQU	07H		;BELL CHARACTER
BS	EQU	08H		;BACK SPACE
CNTRLC	EQU	03H		;CONTROL C
CNTRLD	EQU	04H		;CONTROL D
NULL	EQU	00H		;NULL
	;
$EJECT
	;
	; The internal system equates
	;
LINLEN	EQU	73		;THE LENGTH OF AN INPUT LINE
EOF	EQU	01		;END OF FILE CHARACTER
ASTKAH	EQU	01		;ASTKA IS IN PAGE 1 OF RAM
CSTKAH	EQU	00		;CSTKA IS IN PAGE 0 OF RAM
FTYPE	EQU	01		;CONTROL STACK "FOR"
GTYPE	EQU	02		;CONTROL STACK "GOSUB"
DTYPE	EQU	03		;DO-WHILE/UNTIL TYPE
ROMADR	EQU	8000H		;LOCATION OF ROM
	;
	; The floating point equates
	;
FPSIZ	EQU	6		;NO. OF BYTES IN A FLOATING NUM
DIGIT	EQU	FPSIZ-2		;THE MANTISSA OF A FLOATING NUM
STESIZ	EQU	FPSIZ+3		;SIZE OF SYMBOL ADJUSTED TABLE ELEMENT
FP_BASE	EQU	1993H		;BASE OF FLOATING POINT ROUTINES
PSTART	EQU	512		;START OF A PROGRAM IN RAM
FSIZE	EQU	FPSIZ+FPSIZ+2+2+1
	;
$EJECT
	;**************************************************************
	;
USENT:	; User entry jump table
	;
	;**************************************************************
	;
	DW	CMND1		;(00, 00H)COMMAND MODE JUMP
	DW	IFIX		;(01, 01H)CONVERT FP TO INT
	DW	PUSHAS		;(02, 02H)PUSH VALUE ONTO ARG STACK
	DW	POPAS		;(03, 03H)POP VALUE OFF ARG STACK
	DW	PG1		;(04, 04H)PROGRAM A PROM
	DW	INLINE		;(05, 05H)INPUT A LINE
	DW	UPRNT		;(06, 06H)PRINT A LINR
	DW	CRLF		;(07, 07H)OUTPUT A CRLF
	;
	;**************************************************************
	;
	; This is the operation jump table for arithmetics
	;
	;**************************************************************
	;
OPTAB:	DW	ALPAR		;(08, 08H)LEFT PAREN
	DW	AEXP		;(09, 09H)EXPONENTAION
	DW	AMUL		;(10, 0AH)FP MUL
	DW	AADD		;(11, 0BH)FLOATING POINT ADD
	DW	ADIV		;(12, 0CH)FLOATING POINT DIVIDE
	DW	ASUB		;(13, 0DH)FLOATING POINT SUBTRACTION
	DW	AXRL		;(14, 0EH)XOR
	DW	AANL		;(15, 0FH)AND
	DW	AORL		;(16, 10H)OR
	DW	ANEG		;(17, 11H)NEGATE
	DW	AEQ		;(18, 12H)EQUAL
	DW	AGE		;(19, 13H)GREATER THAN OR EQUAL
	DW	ALE		;(20, 14H)LESS THAN OR EQUAL
	DW	ANE		;(21, 15H)NOT EQUAL
	DW	ALT		;(22, 16H)LESS THAN
	DW	AGT		;(23, 17H)GREATER THAN
	;
$EJECT
	;***************************************************************
	;
	; This is the jump table for unary operators
	;
	;***************************************************************
	;
	DW	AABS		;(24, 18H)ABSOLUTE VALUE
	DW	AINT		;(25, 19H)INTEGER OPERATOR
	DW	ASGN		;(26, 1AH)SIGN OPERATOR
	DW	ANOT		;(27, 1BH)ONE'S COMPLEMENT
	DW	ACOS		;(28, 1CH)COSINE
	DW	ATAN		;(29, 1DH)TANGENT
	DW	ASIN		;(30, 1EH)SINE
	DW	ASQR		;(31, 1FH)SQUARE ROOT
	DW	ACBYTE		;(32, 20H)READ CODE
	DW	AETOX		;(33, 21H)E TO THE X
	DW	AATAN		;(34, 22H)ARC TANGENT
	DW	ALN		;(35, 23H)NATURAL LOG
	DW	ADBYTE		;(36, 24H)READ DATA MEMORY
	DW	AXBYTE		;(37, 25H)READ EXTERNAL MEMORY
	DW	PIPI		;(38, 26H)PI
	DW	ARND		;(39, 27H)RANDOM NUMBER
	DW	AGET		;(40, 28H)GET INPUT CHARACTER
	DW	AFREE		;(41, 29H)COMPUTE #BYTES FREE
	DW	ALEN		;(42, 2AH) COMPUTE LEN OF PORGRAM
	DW	AXTAL		;(43, 2BH) CRYSTAL
	DW	PMTOP		;(44, 2CH)TOP OF MEMORY
	DW	ATIME		;(45, 2DH) TIME
	DW	A_IE		;(46, 2EH) IE
	DW	A_IP		;(47, 2FH) IP
	DW	ATIM0		;(48, 30H) TIMER 0
	DW	ATIM1		;(49, 31H) TIMER 1
	DW	ATIM2		;(50, 32H) TIMER 2
	DW	AT2CON		;(51, 33H) T2CON
	DW	ATCON		;(52, 34H) TCON
	DW	ATMOD		;(53, 35H) ATMOD
	DW	ARCAP2		;(54, 36H) RCAP2
	DW	AP1		;(55, 37H) P1
	DW	APCON		;(56, 38H) PCON
	DW	EXPRB		;(57, 39H) EVALUATE AN EXPRESSION
	DW	AXTAL1		;(58, 3AH) CALCULATE CRYSTAL
	DW	LINE		;(59, 3BH) EDIT A LINE
	DW	PP		;(60, 3CH) PROCESS A LINE
	DW	UPPL-3		;(61, 3DH) UNPROCESS A LINE
	DW	VAR		;(62, 3EH) FIND A VARIABLE
	DW	GC		;(63, 3FH) GET A CHARACTER
	DW	GCI		;(64, 40H) GET CHARACTER AND INCREMENT
	DW	INCHAR		;(65, 41H) INPUT A CHARACTER
	DW	CRUN		;(66, 42H) RUN A PROGRAM
$EJECT
OPBOL:	DB	1		;
	;
	DB	15		;LEFT PAREN
	DB	14		;EXPONENTIAN **
	DB	10		;MUL
	DB	8		;ADD
	DB	10		;DIVIDE
	DB	8		;SUB
	DB	3		;XOR
	DB	5		;AND
	DB	4		;OR
	DB	12		;NEGATE
	DB	6		;EQ
	DB	6		;GT
	DB	6		;LT
	DB	6		;NE
	DB	6		;LE
	DB	6		;GE
	;
UOPBOL:	DB	15		;AABS
	DB	15		;AAINT
	DB	15		;ASGN
	DB	15		;ANOT
	DB	15		;ACOS
	DB	15		;ATAN
	DB	15		;ASIN
	DB	15		;ASQR
	DB	15		;ACBYTE
	DB	15		;E TO THE X
	DB	15		;AATAN
	DB	15		;NATURAL LOG
	DB	15		;DBYTE
	DB	15		;XBYTE
	;
$EJECT
	;***************************************************************
	;
	; The ASCII printed messages.
	;
	;***************************************************************
	;
STP:	DB	'STOP"'
	;
IAN:	DB	'TRY AGAIN"'
	;
RDYS:	DB	'READY"'
	;
INS:	DB	' - IN LINE "'
	;
	;**************************************************************
	;
	; This is the command jump table
	;
	;**************************************************************
	;
CMNDD:	DW	CRUN		;RUN
	DW	CLIST		;LIST
	DW	CNULL		;NULL
	DW	CNEW		;NEW
	DW	CCONT		;CONTINUE
	DW	CPROG		;PROGRAM A PROM
	DW	CXFER		;TRANSFER FROM ROM TO RAM
	DW	CRAM		;RAM MODE
	DW	CROM		;ROM MODE
	DW	CIPROG		;INTELLIGENT PROM PROGRAMMING
	;
$EJECT
	;***************************************************************
	;
	; This is the statement jump table.
	;
	;**************************************************************
	;
STATD:	;
	DW	SLET		;LET		80H
	DW	SCLR		;CLEAR		81H
	DW	SPUSH		;PUSH VAR	82H
	DW	SGOTO		;GO TO		83H
	DW	STONE		;TONE		84H
	DW	SPH0		;PRINT MODE 0	85H
	DW	SUI		;USER INPUT	86H
	DW	SUO		;USER OUTPUT	87H
	DW	SPOP		;POP VAR	88H
	DW	SPRINT		;PRINT		89H
	DW	SCALL		;CALL		8AH
	DW	SDIMX		;DIMENSION	8BH
	DW	STRING		;STRING ALLO	8CH
	DW	SBAUD		;SET BAUD	8DH
	DW	SCLOCK		;CLOCK		8EH
	DW	SPH1		;PRINT MODE 1   8FH
	;
	; No direct mode from here on
	;
	DW	SSTOP		;STOP		90H
	DW	SOT		;ON TIME	91H
	DW	SONEXT		;ON EXT INT	92H
	DW	SRETI		;RET FROM INT	93H
	DW	S_DO		;DO		94H
	DW	SRESTR		;RESTOR		95H
	DW	WCR		;REM		96H
	DW	SNEXT		;NEXT		97H
	DW	SONERR		;ON ERROR	98H
	DW	S_ON		;ON		99H
	DW	SINPUT		;INPUT		9AH
	DW	SREAD		;READ		9BH
	DW	FINDCR		;DATA		9CH
	DW	SRETRN		;RETURN		9DH
	DW	SIF		;IF		9EH
	DW	SGOSUB		;GOSUB		9FH
	DW	SFOR		;FOR		A0H
	DW	SWHILE		;WHILE		A1H
	DW	SUNTIL		;UNTIL		A2H
	DW	CMND1		;END		A3H
	DW	I_DL		;IDLE		A4H
	DW	ST_A		;STORE AT	A5H
	DW	LD_A		;LOAD AT	A6H
	DW	PGU		;PGM		A7H
	DW	RROM		;RUN A ROM	A9H
	;
$EJECT
	;**************************************************************
	;
TOKTAB:	; This is the basic token table
	;
	;**************************************************************
	;