Fixing bug regarding command queue (whoops)

3 files changed, 22 insertions, 20 deletions

diff --git a/README b/README
index c38e043..28aac4b 100644
--- a/README
+++ b/README
@@ -7,12 +7,12 @@
        |   |         |_   |_     ___  |   |     |   | |   |     |   |
        |   |_______    |_   |___|  _| |   |     |   | |_  |_____|  _|
        |___________|     |________|   |___|     |___|   |_________|
-    ___ ___ _ _ ___ __    ___ ___ ___ _ ___ ___                   _   ___ 
-   |  _|   | | |   |  \  |  _|   |  _| |   |  _|                 | | |  _|
-   | |_| | | | | | | | | | |_| | | |_| | | | |_   _ _ ___ ___    | | | |_
-   |_  | | | | | | | | | |  _| | | | | | | |  _| | | | __| _ \   | | |   |
-    _| | | | | | | | | | | |_| | | | | | | | |_  | | | __|   /_  | |_| | |
-   |___|___|___|_|_|__/  |___|_|_|___|_|_|_|___|  \_/|___|_|_\_| |_|_|___|
+   ___ ___ _ _ ___ __    ___ ___ ___ _ ___ ___                   _   ___ _ 
+  |  _|   | | |   |  \  |  _|   |  _| |   |  _|                 | | |  _| |
+  | |_| | | | | | | | | | |_| | | |_| | | | |_   _ _ ___ ___    | | | |_| |
+  |_  | | | | | | | | | |  _| | | | | | | |  _| | | | __| _ \   | | |   | |
+   _| | | | | | | | | | | |_| | | | | | | | |_  | | | __|   /_  | |_| | | |
+  |___|___|___|_|_|__/  |___|_|_|___|_|_|_|___|  \_/|___|_|_\_| |_|_|___|_|
 
 =============================================================================
 
diff --git a/c/echo.c b/c/echo.c
index ed634db..e2d68d9 100644
--- a/c/echo.c
+++ b/c/echo.c
@@ -62,6 +62,7 @@ void echo_init(const void* const* list) {
    // would tell it to load the instrument list, but we can't do that here
    // due to linker shenanigans)
    z80_ram[0x1FFF] = 0x00;
+   z80_ram[0x1FFB] = 0x00;
    
    // Direct stream is empty yet
    z80_ram[0x1F00] = 0xFF;
diff --git a/src-68k/echo.68k b/src-68k/echo.68k
index e755d19..ac3b702 100644
--- a/src-68k/echo.68k
+++ b/src-68k/echo.68k
@@ -123,7 +123,7 @@ Echo_SendCommandEx:
 ;****************************************************************************
 
 Echo_SendCommandByte:
-    movem.l d1/a1, -(sp)            ; Save registers
+    movem.l d1-2/a1, -(sp)          ; Save registers
     Echo_Z80Request                 ; We need the Z80 bus
 
     lea     ($A01FFF), a1           ; First try the 1st slot
@@ -135,8 +135,8 @@ Echo_SendCommandByte:
     tst.b   (a1)                    ; Check if 2nd slot is ready
     beq.s   @Ready                  ; Too busy?
     Echo_Z80Release                   ; Let Echo continue
-    move.w  #$FF, d1                  ; Give it some time
-    dbf     d1, *                       ; ...
+    move.w  #$FF, d2                  ; Give it some time
+    dbf     d2, *                       ; ...
     Echo_Z80Request                   ; Get Z80 bus back
     bra.s   @Try                      ; Try again
 
@@ -145,7 +145,7 @@ Echo_SendCommandByte:
     move.b  d1, -3(a1)              ; Write parameter
     Echo_Z80Release                 ; We're done with the Z80 bus
 
-    movem.l (sp)+, d1/a1            ; Restore registers
+    movem.l (sp)+, d1-d2/a1         ; Restore registers
     rts                             ; End of subroutine
 
 ;****************************************************************************
@@ -403,7 +403,7 @@ Echo_SetVolumeEx:
 ;****************************************************************************
 
 Echo_GetStatus:
-    movem.l d1/a1, -(sp)            ; Save registers
+    movem.l d1-d2/a1, -(sp)         ; Save registers
 
     clr.w   d0                      ; Set all needed bits to 0
     Echo_Z80Request                 ; We need the Z80 bus
@@ -424,21 +424,21 @@ Echo_GetStatus:
     
     move.b  ($A01FFF), d1           ; Get next pending command (if any)
     beq.s   @QueueChecked           ; No commands left to process?
-    move.b  (a1,d1.w), d1           ; Get mask of flags to leave
-    and.b   d1, d0                  ; Remove flags that should be clear
-    move.b  @OrTable-@AndTable(a1,d1.w), d1 ; Get mask of flags to set
-    or.b    d1, d0                  ; Insert flags that should be set
+    move.b  (a1,d1.w), d2           ; Get mask of flags to leave
+    and.b   d2, d0                  ; Remove flags that should be clear
+    move.b  @OrTable-@AndTable(a1,d1.w), d2 ; Get mask of flags to set
+    or.b    d2, d0                  ; Insert flags that should be set
 
     move.b  ($A01FFB), d1           ; Repeat that with 2nd pending command
     beq.s   @QueueChecked
-    move.b  (a1,d1.w), d1
-    and.b   d1, d0
-    move.b  @OrTable-@AndTable(a1,d1.w), d1
-    or.b    d1, d0
+    move.b  (a1,d1.w), d2
+    and.b   d2, d0
+    move.b  @OrTable-@AndTable(a1,d1.w), d2
+    or.b    d2, d0
 
 @QueueChecked:
     Echo_Z80Release                 ; Let the Z80 go!
-    movem.l (sp)+, d1/a1            ; Restore registers
+    movem.l (sp)+, d1-d2/a1         ; Restore registers
     rts                             ; End of subroutine
 
 ;----------------------------------------------------------------------------
@@ -545,6 +545,7 @@ Echo_Init:
     Echo_Z80Request                 ; We need the Z80 bus
 
     move.b  #$01, ($A01FFF)         ; Command: load pointer list
+    move.b  #$00, ($A01FFB)         ; No other command yet
 
     move.l  a0, d0                  ; Easier to manipulate here
     move.b  d0, ($A01FFD)           ; Store low address byte