Stereo System User Manual

9 - 6 DSP96002 USER’S MANUAL MOTOROLA
; Host load routine
_HOSTR
_LBL11 JCLR #3,X:(R2),_LBL22 ; if HF0=1, stop loading data.
ENDDO ; Must terminate the do loops
JMP <_BOOTEND
_LBL22 JCLR #0,X:(R2),_LBL11 ; Wait for HRDF to go high
; (meaning data is present).
JCLR #4,X:(R2),_LBL33 ; 8-bit source?
MOVE X:(R3),D0.L ; Get 32-bit word from host
JMP <_STORE
_LBL33 DO #4,_LOOP4 ; Get 4 bytes into D0.L
LSR #8,D0 ; Shift previous byte down
_LBL1 JCLR #3,X:(R2),_LBL2 ; if HF0=1, stop loading data.
ENDDO ; Must terminate the do loops
ENDDO
JMP <_BOOTEND
_LBL2 JCLR #0,X:(R2),_LBL1 ; Wait for HRDF to go high
; (meaning data is present).
MOVE X:(R3),D1.L ; Get byte from host
LSL #24,D1 ; Shift into upper byte
OR D1,D0 ; concatenate
_LOOP4
_STORE MOVEM D0.L,P:(R0)+ ; Store 32-bit result in P mem.
_LOOP1 ; and go get another 32-bit word
; This is the exit handler that returns execution to internal PRAM
_BOOTEND ANDI #$F9,OMR ; Set the operating mode to 00x
; (and trigger an exit from
; bootstrap mode).
ANDI #$0,CCR ; Clear CCR as if HW RESET.
; Also delay needed for
; Op. Mode change.
JMP <$0 ; Start fetching from PRAM.
; DSP96002 bootstrap program size = 50 words
Figure 9-3. Assembler Source for DSP96002 Bootstrap Program (3 of 3)
9.2 DATA MEMORY MAPS
The data memory maps are shown in Figure 9-4 and Figure 9-5.