Changes
<pre>
;; This example shows how to access the firmware from within CP/M+.
;; This example does not work with CP/M2.2
;;
;;---------------------------------------------------------
org &100 ;; origin for C/PM .COM programs
nolist
write"test2.com"
.scr_set_mode equ &bc0e
.txt_output equ &bb5a
;;---------------------------------------------------------
;; get address of routine to call to execute
;; a firmware function
ld hl,(&0001)
ld de,&0057
add hl,de
ld (firm_jump+1),hl
;;---------------------------------------------------------
;; change the display mode to mode 1
ld a,1
call firm_jump
defw scr_set_mode
;; display a message on the screen
ld hl,test_message
call display_message
;; quit back to command-line
ret
;;---------------------------------------------------------
;; HL = pointer to null terminated message
.display_message
ld a,(hl) ;; get ASCII character
inc hl ;; increment pointer for next character
or a ;; end of message marker (0)?
ret z ;; quit if end of message marker found.
call display_char ;; send character to console output
jp display_message ;; loop for next char
;;---------------------------------------------------------
.display_char
call firm_jump
defw txt_output ;; firmware function: TXT OUTPUT
ret
;;---------------------------------------------------------
;; execute a firmware function
.firm_jump
jp 0
;;---------------------------------------------------------
.test_message
defb "Hello World!",0
</pre>
;; This example shows how to access the firmware from within CP/M+.
;; This example does not work with CP/M2.2
;;
;;---------------------------------------------------------
org &100 ;; origin for C/PM .COM programs
nolist
write"test2.com"
.scr_set_mode equ &bc0e
.txt_output equ &bb5a
;;---------------------------------------------------------
;; get address of routine to call to execute
;; a firmware function
ld hl,(&0001)
ld de,&0057
add hl,de
ld (firm_jump+1),hl
;;---------------------------------------------------------
;; change the display mode to mode 1
ld a,1
call firm_jump
defw scr_set_mode
;; display a message on the screen
ld hl,test_message
call display_message
;; quit back to command-line
ret
;;---------------------------------------------------------
;; HL = pointer to null terminated message
.display_message
ld a,(hl) ;; get ASCII character
inc hl ;; increment pointer for next character
or a ;; end of message marker (0)?
ret z ;; quit if end of message marker found.
call display_char ;; send character to console output
jp display_message ;; loop for next char
;;---------------------------------------------------------
.display_char
call firm_jump
defw txt_output ;; firmware function: TXT OUTPUT
ret
;;---------------------------------------------------------
;; execute a firmware function
.firm_jump
jp 0
;;---------------------------------------------------------
.test_message
defb "Hello World!",0
</pre>
