Fixed MTP to work with TWRP

firmware/dsp56k/bootstrap.asm

@@ -0,0 +1,98 @@
+; Author: Frederik Noring <noring@nocrew.org>
+;
+; This file is subject to the terms and conditions of the GNU General Public
+; License.  See the file COPYING in the main directory of this archive
+; for more details.
+
+; DSP56k loader
+
+; Host Interface
+M_BCR   EQU     $FFFE           ; Port A Bus Control Register
+M_PBC   EQU     $FFE0           ; Port B Control Register
+M_PBDDR EQU     $FFE2           ; Port B Data Direction Register
+M_PBD   EQU     $FFE4           ; Port B Data Register
+M_PCC   EQU     $FFE1           ; Port C Control Register
+M_PCDDR EQU     $FFE3           ; Port C Data Direction Register
+M_PCD   EQU     $FFE5           ; Port C Data Register
+
+M_HCR   EQU     $FFE8           ; Host Control Register
+M_HSR   EQU     $FFE9           ; Host Status Register
+M_HRX   EQU     $FFEB           ; Host Receive Data Register
+M_HTX   EQU     $FFEB           ; Host Transmit Data Register
+
+; SSI, Synchronous Serial Interface
+M_RX    EQU     $FFEF           ; Serial Receive Data Register
+M_TX    EQU     $FFEF           ; Serial Transmit Data Register
+M_CRA   EQU     $FFEC           ; SSI Control Register A
+M_CRB   EQU     $FFED           ; SSI Control Register B
+M_SR    EQU     $FFEE           ; SSI Status Register
+M_TSR   EQU     $FFEE           ; SSI Time Slot Register
+
+; Exception Processing
+M_IPR   EQU     $FFFF           ; Interrupt Priority Register
+
+        org     P:$0
+start   jmp     <$40
+
+        org     P:$40
+;       ; Zero 16384 DSP X and Y words
+;       clr     A #0,r0
+;       clr     B #0,r4
+;       do      #64,<_block1
+;       rep     #256
+;       move    A,X:(r0)+ B,Y:(r4)+
+;_block1        ; Zero (32768-512) Program words
+;       clr     A #512,r0
+;       do      #126,<_block2
+;       rep     #256
+;       move    A,P:(r0)+
+;_block2
+
+        ; Copy DSP program control
+        move    #real,r0
+        move    #upload,r1
+        do      #upload_end-upload,_copy
+        movem    P:(r0)+,x0
+        movem    x0,P:(r1)+
+_copy   movep   #4,X:<<M_HCR
+        movep   #$c00,X:<<M_IPR
+        and     #<$fe,mr
+        jmp     upload
+
+real
+        org     P:$7ea9
+upload
+        movep   #1,X:<<M_PBC
+        movep   #0,X:<<M_BCR
+
+next    jclr    #0,X:<<M_HSR,*
+        movep   X:<<M_HRX,A
+        move    #>3,x0
+        cmp     x0,A #>1,x0
+        jeq     <$0
+_get_address
+        jclr    #0,X:<<M_HSR,_get_address
+        movep   X:<<M_HRX,r0
+_get_length
+        jclr    #0,X:<<M_HSR,_get_length
+        movep   X:<<M_HRX,y0
+        cmp     x0,A #>2,x0
+        jeq     load_X
+        cmp     x0,A
+        jeq     load_Y
+
+load_P  do      y0,_load_P
+        jclr    #0,X:<<M_HSR,*
+        movep   X:<<M_HRX,P:(r0)+
+_load_P jmp     next
+load_X  do      y0,_load_X
+        jclr    #0,X:<<M_HSR,*
+        movep   X:<<M_HRX,X:(r0)+
+_load_X jmp     next
+load_Y  do      y0,_load_Y
+        jclr    #0,X:<<M_HSR,*
+        movep   X:<<M_HRX,Y:(r0)+
+_load_Y jmp     next
+
+upload_end
+        end