Figured out $8E00 call - redraws desktop icons.

Also found a couple bugs:
https://github.com/inexorabletash/a2d/issues/33
https://github.com/inexorabletash/a2d/issues/34

desk.acc/a2d.inc

@@ -3,17 +3,9 @@
 ;;; ==================================================
 
 ;;; ==================================================
-;;; Entry Points
+;;; Direct Calls
 
-A2D             := $4000
-
-UNKNOWN_CALL    := $8E00
-        ;; MLI-style call (call, addr)
-        ;; Bounces to $93BC
-        ;; References jump table at 939E
-
-
-        ;; These must be called from main memory (RAMRDON/RAMWRTON)
+        ;; These must be called from main memory (RAMRDOFF/RAMWRTOFF)
 JUMP_TABLE_03   := $4003        ; ???
 JUMP_TABLE_06   := $4006        ; ???
 JUMP_TABLE_09   := $4009        ; ???
@@ -38,6 +30,11 @@ JUMP_TABLE_3F   := $403F        ; ???
 ;;; ==================================================
 ;;; A2D Calls
 
+A2D             := $4000
+        ;; MLI-style call (jsr A2D ; .byte call ; .addr params)
+        ;; Call from AUX (RAMRDON/RAMWRTON)
+
+
 ;;; $40E5,(call*2) is the jump table used for processing these calls
 ;;; $4184,(call*2) defines param blocks input length
 ;;;   if >=0, is length of param block
@@ -386,6 +383,18 @@ A2D_CWS_SCROLL_NORMAL  := A2D_CWS_SCROLL_ENABLED | A2D_CWS_SCROLL_THUMB | A2D_CW
 A2D_DEFAULT_MSKAND := $FF
 A2D_DEFAULT_MSKOR  := $00
 
+;;; ==================================================
+
+DESKTOP    := $8E00
+        ;; MLI-style call (jsr A2D ; .byte call ; .addr params)
+        ;; Call from AUX (RAMRDON/RAMWRTON)
+
+        ;; Implementation bounces to $93BC, uses jump table at $939E
+
+;;; This is the only known call:
+
+DESKTOP_REDRAW_ICONS := $0C     ; Repaints desktop icons
+
 ;;; ==================================================
 ;;; Macros
 
@@ -409,6 +418,26 @@ A2D_DEFAULT_MSKOR  := $00
 .endif
 .endmacro
 
+;;; ------------------------------------
+;;; Same as above, but for DESKTOP
+
+.macro  DESKTOP_CALL    op, addr, label
+        jsr DESKTOP
+        .byte op
+
+.if .paramcount > 2
+        label := *
+.endif
+
+.if .paramcount > 1
+        .addr addr
+.else
+        .addr 0
+.endif
+.endmacro
+
+;;; ------------------------------------
+
 .macro A2D_DEFSTRING str, label ; String definition, for use with A2D_TEXT
         .local  data            ; Call as A2D_DEFSTRING "abc"
         .local  end             ; Can include control chars by using:

desk.acc/calculator.s

@@ -102,12 +102,10 @@ call_init:
         ;; ???
         lda     LCBANK1
         lda     LCBANK1
-        bit     redraw_flag
 
+        bit     redraw_flag     ; BUG: https://github.com/inexorabletash/a2d/issues/33
         bmi     skip
-        jsr     UNKNOWN_CALL
-        .byte   $0C
-        .addr   0
+        DESKTOP_CALL DESKTOP_REDRAW_ICONS
 
         ;; ???
 skip:   lda     #0
@@ -144,6 +142,8 @@ redraw_flag:  .byte   0         ; ???
         sta     redraw_flag
         rts
 
+        ;; Is skipping this responsible for display redraw bug?
+        ;; https://github.com/inexorabletash/a2d/issues/34
 :       A2D_CALL A2D_QUERY_STATE, query_state_params
         A2D_CALL A2D_SET_STATE, state_params
         lda     query_state_params_id
@@ -891,9 +891,7 @@ ignore_click:
 exit:   lda     LCBANK1
         lda     LCBANK1
         A2D_CALL A2D_DESTROY_WINDOW, destroy_window_params
-        jsr     UNKNOWN_CALL
-        .byte   $0C
-        .addr   0
+        DESKTOP_CALL DESKTOP_REDRAW_ICONS
         lda     ROMIN2
         A2D_CALL $1A, L08D5     ; ??? one byte input value?
 

desk.acc/date.s

@@ -658,9 +658,7 @@ dialog_result:  .byte   0
 
 .proc destroy
         A2D_CALL A2D_DESTROY_WINDOW, destroy_window_params
-        jsr     UNKNOWN_CALL
-        .byte   $0C
-        .addr   0
+        DESKTOP_CALL DESKTOP_REDRAW_ICONS
 
         ;; Copy the relay routine to the zero page
         dest := $20

desk.acc/puzzle.s

@@ -99,9 +99,7 @@ loop:   lda     routine,x
         bit     window_pos_flag
         bmi     skip
 
-        jsr     UNKNOWN_CALL    ; update window pos?
-        .byte   $0C
-        .addr   0
+        DESKTOP_CALL DESKTOP_REDRAW_ICONS
 
 skip:   lda     #0
         sta     window_pos_flag
@@ -735,10 +733,7 @@ bail:   rts
         beq     bail
 destroy:
         A2D_CALL A2D_DESTROY_WINDOW, destroy_window_params
-
-        jsr     UNKNOWN_CALL    ; ???
-        .byte   $0C
-        .addr   0
+        DESKTOP_CALL DESKTOP_REDRAW_ICONS
 
         target = $20            ; copy following to ZP and run it
         ldx     #sizeof_routine

desk.acc/show_image_file.s

@@ -377,13 +377,9 @@ end:    rts
         bne     input_loop      ; nope, keep waiting
 
         A2D_CALL A2D_DESTROY_WINDOW, window_params
-
+        DESKTOP_CALL DESKTOP_REDRAW_ICONS
         jsr     unstash_menu
 
-        jsr     UNKNOWN_CALL    ; ???
-        .byte   $0C
-        .addr   0
-
         rts                     ; exits input loop
 .endproc
 

desk.acc/show_text_file.s

@@ -549,11 +549,7 @@ title:  jsr     on_title_bar_click
         beq     input_loop      ; nope
         jsr     close_file
         A2D_CALL A2D_DESTROY_WINDOW, window_params
-
-        jsr     UNKNOWN_CALL    ; ???
-        .byte   $0C
-        .addr   0
-
+        DESKTOP_CALL DESKTOP_REDRAW_ICONS
         rts                     ; exits input loop
 .endproc
 
@@ -948,9 +944,7 @@ end:    rts
 .endproc
 
 .proc finish_resize             ; only called from dead code
-        jsr     UNKNOWN_CALL
-        .byte   $0C
-        .addr   0
+        DESKTOP_CALL DESKTOP_REDRAW_ICONS
         A2D_CALL A2D_SET_STATE, window_params::box
         lda     window_params::hscroll
         ror     a               ; check if low bit (track enabled) is set