Code Composer's linker is unexpectedly adding a "RRCM.A #1, PC" assembly instruction into the compiled code when optimizing with --opt_level=0. This causes the program to execute an invalid flash location, crashing the program. The problem does not seem to occur (or I have not found it yet) with --opt_level=2. I have not tested it at other optimization levels.
The relevant C code I used was:
#define CMD0 (0x40+0) /* GO_IDLE_STATE */
unsigned char send_cmd ( unsigned char, unsigned long );
unsigned char disk_initialize( unsigned char drv )
{
unsigned char ty;
... [some code here]
ty = 0;
if (send_cmd(CMD0, 0) == 1) {
... [some code here]
}
This is what the assembly looks like:
$C$DW$L$disk_initialize$6$E:
;* --------------------------------------------------------------------------*
$C$L22:
.dwpsn file "../FatFs/mmc.c",line 279,column 2,is_stmt
;----------------------------------------------------------------------
; 279 | ty = 0;
;----------------------------------------------------------------------
MOV.B #0,r9 ; [] |279|
.dwpsn file "../FatFs/mmc.c",line 280,column 2,is_stmt
;----------------------------------------------------------------------
; 280 | if (send_cmd(CMD0, 0) == 1) { /* Enter Idle state */
;----------------------------------------------------------------------
MOV.B #64,r12 ; [] |280|
MOV.W #0,r13 ; [] |280|
MOV.W #0,r14 ; [] |280|
$C$DW$90 .dwtag DW_TAG_TI_branch
.dwattr $C$DW$90, DW_AT_low_pc(0x00)
.dwattr $C$DW$90, DW_AT_name("send_cmd")
.dwattr $C$DW$90, DW_AT_TI_call
CALL #send_cmd ; [] |280|
; [] |280|
CMP.B #1,r12 ; [] |280|
JNE $C$L35 ; [] |280|
; [] |280|
However, the code that is linked and downloaded to my target looks like this:
C$L22, C$DW$L$disk_initialize$6$E:
0x076a2: 4349 CLR.B R9
0x076a4: 407C 0040 MOV.B #0x0040,R12
0x076a6: 0040 RRCM.A #1,PC
0x076a8: 430D CLR.W R13
0x076aa: 430E CLR.W R14
0x076ac: 12B0 8C44 CALL #send_cmd
0x076b0: 935C CMP.B #1,R12
0x076b2: 2073 JNE (C$L35)
That RRCM.A #1,PC was not in the compiler listing, it appears as though the linker added it unexpectedly.
Dan.
