From 231d03b548ab6a02c5c94ff82445bf0210a770df Mon Sep 17 00:00:00 2001
From: Joshua Bell <inexorabletash@gmail.com>
Date: Thu, 27 Dec 2018 12:55:56 -0800
Subject: [PATCH] RBH DA: Restore devices and reformat /RAM. Fixes #98

---
 desk.acc/run.basic.here.s | 49 +++++++++++++++++++++++++++++++++++++--
 desktop.inc               |  4 ++++
 desktop/desktop_res.s     |  3 ++-
 3 files changed, 53 insertions(+), 3 deletions(-)

diff --git a/desk.acc/run.basic.here.s b/desk.acc/run.basic.here.s
index 035720c..568c509 100644
--- a/desk.acc/run.basic.here.s
+++ b/desk.acc/run.basic.here.s
@@ -50,8 +50,11 @@ start:
         lda     #$FE            ; "BASIC.SYSTEM not found"
         bne     fail
 
+        ;; Restore devices DeskTop may have removed
+:       jsr     restore_device_list
+
         ;; Restore to normal state
-:       sta     ALTZPOFF
+        sta     ALTZPOFF
         lda     ROMIN2
         jsr     SETVID
         jsr     SETKBD
@@ -66,7 +69,8 @@ start:
         sta     CLR80VID
         sta     CLR80COL
 
-        ;; TODO: restore /RAM?
+        ;; Reformat /RAM if it was restored
+        jsr     maybe_reformat_ram
 
         ;; Set PREFIX
         MLI_CALL SET_PREFIX, set_prefix_params
@@ -221,3 +225,44 @@ fail:   return  #1
 .endproc
 
 ;;; ============================================================
+
+.proc restore_device_list
+        ldx     devlst_backup
+        inx
+:       copy    devlst_backup,x, DEVLST-1,x
+        dex
+        bpl     :-
+        rts
+.endproc
+
+;;; ============================================================
+
+.proc maybe_reformat_ram
+        ram_unit_number = (1<<7 | 3<<4 | DT_RAM)
+
+        ;; Search DEVLST to see if S3D2 RAM was restored
+        ldx     DEVCNT
+:       lda     DEVLST,x
+        cmp     #ram_unit_number
+        beq     format
+        dex
+        bpl     :-
+        rts
+
+        ;; NOTE: Assumes driver (in DEVADR) was not modified
+        ;; when detached.
+
+        ;; /RAM FORMAT call; see ProDOS 8 TRM 5.2.2.4 for details
+format: copy    #DRIVER_COMMAND_FORMAT, DRIVER_COMMAND
+        copy    #ram_unit_number, DRIVER_UNIT_NUMBER
+        copy16  #$2000, DRIVER_BUFFER
+        lda     LCBANK1
+        lda     LCBANK1
+        jsr     driver
+        sta     ROMIN2
+        rts
+
+RAMSLOT := DEVADR + $16         ; Slot 3, Drive 2
+
+driver: jmp     (RAMSLOT)
+.endproc
diff --git a/desktop.inc b/desktop.inc
index 023b2e6..cdb9325 100644
--- a/desktop.inc
+++ b/desktop.inc
@@ -171,6 +171,10 @@ path_table := $DFB3     ; window address table
 selected_file_list := $DF22     ; indexes of selected file (global, not w/in window, up to 127)
 file_table := $DD9F     ; file address table
 
+;;; Copy of DEVLST before DeskTop modifies it. Used when exiting or
+;;; invoking to restore devices.
+devlst_backup := $E196
+
 last_menu_click_params := $E25A
 
 ;;; Icon (file/volume) entries - length 27 bytes, maximum of 127
diff --git a/desktop/desktop_res.s b/desktop/desktop_res.s
index ff0c7be..5de38da 100644
--- a/desktop/desktop_res.s
+++ b/desktop/desktop_res.s
@@ -989,7 +989,8 @@ entries_read_this_block:
 ;;; ============================================================
 
         ;; Backup copy of DEVLST made before detaching ramdisk
-devlst_backup:
+devlst_backup_:
+        .assert * = devlst_backup, error, "Entry point mismatch"
         .res    10, 0
 
         ;; index is device number (in DEVLST), value is icon number