Page 52 - The Art of Designing Embedded Systems

Stop Writing Big Programs 39

- text segment

; -get-cba-min-read a min value at (index) from the
; CBA buffer. Called by a C program with the (index)
; argument on the stack.

; Returns result in AX.

public -get-cba-min
- get-cba-min proc far
mov bx, SP
mov bx, [bx+4] ; bx= index in buf to read
add bx, cba-buf ; add offset to make addr
push ds
mov dx,buffer-seg ; point to the buffer seg
mov es , dx
mov ax, es : bx : read the min value
POP ds
retf
endp
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; CBA buffer, which is managed by the *-cba routines.
; Format: 100 entries, each of which looks like:
; buf+0 min value (word)
; buf+2 max value (word)
; buf+4 number of iterations (word)

- data segment para ‘DATA’
cba-bu f ds 100 * 6 ; CBA buffer
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FIWRE 3-1 Encapsulation in assembly language. Note that the data is
not defined Public.