Assembling Files

 

There are three common ways to assemble source files written in

assembly code. Each has a slightly different syntax – if you are–t85 -b myfile.asm myfile.com

getting errors with one, then try another.

1) TASM (on a PC)

2) Microsoft’s M80 assembler (on a CP/M computer)

3) CP/M’s ASM.COM (on a CP/M computer)

************************ TASM ******************************

TSAM is compiled on the PC, and you can create a batch file to save

remembering the syntax. TASM is used to compile the N8VEM eprom code.

Example of TASM submit file (or type it in manually) for Z80 opcodes:

tasm -t80 -b myfile.asm myfile.com

code example

UPCASE:

CP 'a' ;KEEP NUMBERS, CONTROLS

RET C ;AND UPPER CASE

CP 7BH ;SEE IF NOT LOWER CASE

RET NC

AND 5FH ;MAKE UPPER CASE

RET

Or if using 8080 opcodes:

tasm

code example

;

; CONVERT INPUT LINE TO UPPER CASE.

;

GETINP2 LXI H,INBUFF+1

MOV B,M ;(B)=CHARACTER COUNTER.

GETINP3 INX H

MOV A,B ;END OF THE LINE?

ORA A

JZ GETINP4

MOV A,M ;CONVERT TO UPPER CASE.

CALL UPPER

MOV M,A

DCR B ;ADJUST CHARACTER COUNT.

JMP GETINP3

GETINP4 MOV M,A ;ADD TRAILING NULL.

LXI H,INBUFF+2

SHLD INPOINT ;RESET INPUT LINE POINTER.

RET

************* Using Microsoft’s M80 *********************

This uses M80.com, L80.com and works on .MAC files. On the Walnut

Creek archive about half the source files are .MAC and half are .ASM

so both systems are useful.

This program sets the baud rate to 1200

; 1200 baud

; changing from tasm mnemonics - replace all $nn with nnH

; remove . in front of equ

; remove : in equ lines

; must have a CR/LF after END

; use zasm.sub with supersub

; eg supersub zasm myfile (where myfile is called myfile.mac but do

not put the

; mac in the instruction - m80 knows it is

implied)

; zasm.sub is the following two lines

;M80 =$1 /Z/C/L/M

;L80 $1,$1/N/E

; UART 16C450 SERIAL IS ATTACHED TO THE SECOND IO BASE ADDRESS

IO_Y0 EQU 60h

IO_Y1 EQU 68h

IO_Y2 EQU 70h

IO_Y3 EQU 78h

UART0 EQU IO_Y1+0 ; DATA IN/OUT

UART1 EQU IO_Y1+1 ; CHECK RX

UART2 EQU IO_Y1+2 ; INTERRUPTS

UART3 EQU IO_Y1+3 ; LINE CONTROL

UART4 EQU IO_Y1+4 ; MODEM CONTROL

UART5 EQU IO_Y1+5 ; LINE STATUS

UART6 EQU IO_Y1+6 ; MODEM STATUS

UART7 EQU IO_Y1+7 ; SCRATCH REG.

 

 

UART1200: LD A,80H

OUT (UART3),A ; SET DLAB FLAG

LD A,96 ; = 1,843,200 / ( 16 x 9600 )

OUT (UART0),A ; Set BAUD rate to 1200

LD A,00H

OUT (UART1),A ;

LD A,03H

OUT (UART3),A ; Set 8 bit data, 1 stopbit

ret ; back to CP/M

end

***************** Using CP/M’s ASM.COM program *****************

This uses ASM.COM and LOAD.COM As with M80, don’t type the extension,

it assumes it is a .asm

ASM can handle Z80 or 8080 opcodes.

An example of a submit file is

ASM $1

LOAD $1

 

And an example of code:

FCB EQU 5CH

BDOS EQU 05

FPRT EQU 9

FCLOSE EQU 16

DELETE EQU 19

WRITE EQU 21

MAKE EQU 22

SDMA EQU 26

SRCH EQU 17

SRCHX EQU 18

;

DMA EQU 80H ; DMA LOCATION

;

ORG 100H ;CP/M TPA

;

LXI H,0

DAD SP

SHLD OLDSTK ;SAVE OLD STACK POINTER