1. Introduction to Holtek ASM Programming

2. Section-based Programming
Relocatable segment of code/data
Logical division of program

3. Concept of Relocation Linker section-1 section-2 section-1 section-2

4. Section Syntax Name : .section : alignment: combine: class:
defined by user
reversed word
byte / word / page
at addr / common
code / data

5. Directive Define Variable Data
name DB ?
name DB repeated-count DUP(?)
name DW ?
name DW repeated-count DUP(?)
name DBIT

6. Example
data0 .section ‘data’
var db ?
array db 5 dup(?)
var1 dw ?
Array1 dw 3 dup(?)
flag dbit

7. Directive Define Variable Data
name LABEL BYTE
name DBIT
Example
data .section ‘data’
mySTATUS label byte
C dbit
AC dbit
Z dbit
OV dbit

8. Directive Define Constant Data
[label:] DC expr1[,expr2[,..]]
 must in code section
Example:
code .section ‘code’
MyTable:
DC 0128h, 0ffh, 10h+20h

9. Directive ORG ORG expression  Relative to section beginning eg.
org 0ffh
org 10+20

10. Directive EQU name EQU expression  NOT variable definition eg.
PortA EQU [12h]
bmove EQU mov
Ten EQU 10

11. Directive PROC/ENDP
PROC/ENDP
name PROC
...
(function body)
name ENDP

12. Directive END
END
...
mov a,20h
end
mov a,10h ; ignored

13. Directive PUBLIC & EXTERN
public name[,name].....
code: label
data: data defined by DB, DBIT
extern name:type[,name:type]....
type: near, bit, byte

14. Example public var1 extern func1:near data .section at 40h 'data'
var1 db ?
c1 .section at 0 'code'
mov a,10h
mov var1,a
call func1
jmp $
end
extern var1: byte
public func1
c2 .section 'code'
func1 proc
mov a,var1
add a,010h
ret
func1 endp

15. Directive MACRO/ENDM
name MACRO [param1[,param2]]
LOCAL loc1,loc2
...
ENDM

16. Multiple-defined labels in Macro Expansion
delay Macro
label:
EndM
Solution:
delay Macro
Local label
label:
EndM
...
delay .
label: .
label:

17. Example Macro 1 delay macro para1 2 local a1 3 a1: 4 sdz para1
5 jmp a1
6 endm 7
8 include ht48c30-1.inc
9 data .section 'data'
10 tmp1 db ?
11 code .section 'code'
12 mov a,30h
13 mov tmp1,a
14 delay tmp1
15 delay tmp1
16 jmp $
17 end

18. Directive ConditionalIF
statememts
[ELSE
statements]
ENDIF
IF expression
IFE expression
IFDEF name
IFNDEF name

19. Example Conditional Assembler
1 include ht48c30.inc
2 _debug equ 1
3 code .section 'code'
4 ifdef _debug
5 mov a,10h
6 endif
7 ifndef _debug
8 mov a,20h
9 endif
10 if _debug
11 mov a,30h
12 endif
13 ife _debug
14 mov a,40h
15 endif
16 mov a,50h
17 add a,30h
18 jmp $

20. Directive File Control
.LIST
.NOLIST
.LISTMACRO
.NOLISTMACRO
.LISTINCLUDE
.NOLISTINCLUDE
MESSAGE
INCLUDE

21. Directive Others HIGH/LOW OFFSET SHR/SHL Example:
data .section 'data'
array db 10 dup(?)
code .section 'code'
mov a, b SHR 1 ;7fH
mov a,0ffh AND 0fh ; 0fH
mov a,offset array ;
mov a,LOW 0abcdh ; cdH
mov a,HIGH 0abcd ; abH
jmp $

22. Example: Table Read routine .section page 'code'
; input acc for index,
; output on ‘pattern’
ReadPattern PROC
add A,LOW OFFSET pattern_table
mov TBLP,A
tabrdc pattern[0]
mov A,TBLH
mov pattern[1],A
ret
ReadPattern ENDP
pattern_table:
DC 2332h, 0232h, 1897h
used_data .section 'data'
pattern DB 2 dup(?)

23. Bank (Organization)
ROM
RAM 0H 0H
40H
...
...
1FFFH
FFH BP

24. Bank (Assignment) Format:
ROMBANK <bank> <sec1>,<sec2>,...
Example:
ROMBANK 0 entry,main
ROMBANK 1 routine
entry .section at 0 ‘code’
main .section ‘code’
routine .section ‘code’

25. Bank (Usage) ROM RAM ; modify BP MOV A, NewBP MOV BP, A
; JMP/CALL to switch bank
JMP label
CALL func
; modify BP
MOV A, NewBP
MOV BP, A
; set MP1
MOV A, BankOffset
MOV MP1, A
; read/write thr. R1
MOV R1, A
MOV A, R1

26. Listing File Find syntax error in MACRO/INCLUDE
.listinclude .listmacro
Macro nested level
Offset relative to section
Operand type: external reference/relocatable name

27. Map file Result of section relocation Public symbol
Absolute starting address
Length
Public symbol
sorted by name/offset
What if source too big?