Texas Instruments TMS320C3x User Manual page 730

label4 SUBI
CMPI
BN
label5 CALLU
DBU
*================================================================================*
* Read and save IOSTRB, STRB0 & STRB1 (to be loaded at end of boot load)
*================================================================================*
strobes CALLU
STI
CALLU
STI
CALLU
STI
*================================================================================
* Process block size (# of bytes, half–words, or words after STRB cntrl)
*================================================================================*
block CALLU
LDI
BNZ
LDI
STI
LDI
STI
LDI
STI
BU
label2 LDI
SUBI
*================================================================================*
* Process block destination address, save start address of first block
*================================================================================*
CALLU AR0
LDI R1,AR5
CMPI 0,IR0
LDINZ AR5,IR1
LDINZ 0,IR0
*================================================================================*
* (For internal destination, this word should be 0 or 60h. The first case will
* result in 0 ––> DMA cntrl reg, in second case 0 ––> IOSTRB reg).
* Process block destination strobe control (sss...sss 0110 xx00)
*======================================== strb value ==== 00 – IOSTRB
*
2,AR6
0,AR6
strobes ;*******; total # of mem reads = 32/R5
read_m
AR6,label5 ;****;
AR0
R1,*+AR7(4)
AR0
R1,*+AR7(6)
AR0
R1,*+AR7(8)
AR0
R1,R1
label2 ;*******; no, go around
*+AR7(4),R0
R0,*+AR7(60h)
*+AR7(6),R0
R0,*+AR7(64h)
*+AR7(8),R0
R0,*+AR7(68h)
IR1 ;*******; branch to start of program
R1,RC
1,RC
; set flags
; read memory once
; IOSTRB ––>
; STRB0 ––>
; STRB1 ––>
; read boot memory cntrl word
; is this the last block ?
;
; restore IOSTRB
;
; restore STRB0
;
; restore STRB1
; setup transfer loop
; RC – 1 ––> RC
; read boot memory cntrl word
; set dest addr
; look at EXEC start addr flag
; if –1, EXEC start addr
; set EXEC start addr flag
TMS320C32 Boot Loader Source Code
Boot-Loader Source Code Listing
(DMA src)
(DMA dst)
(DMA cnt)
(DMA src)
(DMA dst)
(DMA cnt)
––> AR5
––> IR1
01 – STRB0
C-7