Add support for INITAD to the Atari binary format.

testcode/lib/atari/multi-xex.cfg

@@ -3,10 +3,12 @@ FEATURES {
 }
 MEMORY {
     ZP:      file = "", define = yes, start = $0082, size = $007E;
+    # First memory segment in file, show message
+    LOADER:  file = %O, start = $680, size = 128;
     # First memory segment in file, load over COLOR registers:
     COLOR:   file = %O, start = $2C4, size = 5;
     # Second memory segment, load at page 6:
-    PAGE6:   file = %O, start = $600, size = 256;
+    PAGE6:   file = %O, start = $600, size = 128;
     # Third memory segment in file, load over SDLST register:
     SDLST:   file = %O, start = $230, size = 2;
     # Main segment, load at "STARTADDRESS"
@@ -16,11 +18,13 @@ FILES {
     %O: format = atari;
 }
 FORMATS {
-    atari: runad = start;
+    atari: runad = start,
+           initad = LOADER: show_load;
 }
 SEGMENTS {
     ZEROPAGE: load = ZP,      type = zp,  optional = yes;
     # Place segments in memory areas:
+    LOADER:   load = LOADER,  type = rw;
     COLOR:    load = COLOR,   type = rw;
     PAGE6:    load = PAGE6,   type = rw;
     SDLST:    load = SDLST,   type = rw;

testcode/lib/atari/multi-xex.s

@@ -14,8 +14,25 @@
         .macpack        atari
 
 ; Default RUNAD is "start", export that:
-        .export         start
+        .export         start, show_load
 
+; Loader
+        .segment        "LOADER"
+show_load:
+        ldx     #0              ; channel 0
+        lda     #<msg_load
+        sta     ICBAL,x         ; address
+        lda     #>msg_load
+        sta     ICBAH,x
+        lda     #$FF
+        sta     ICBLL,x         ; length
+        sta     ICBLH,x
+        lda     #PUTREC
+        sta     ICCOM,x
+        jmp     CIOV
+
+msg_load:
+        .byte   "Loading....", ATEOL
 
 ; We load color values directly into registers
         .segment        "COLOR"