Tool/software: TI C/C++ Compiler
Hello all,
I encounter strange behavior of my program on F28069 and CGT 18.2.2 after a minor (I was wrong I suppose!) change in code. There was not expected spurious memory write that caused device malfunction. The problem was isolated to small simple function (below), that initialized some struct members. The code is like this (I left the real line numbers to correlate with assembly below):
void Func()
{
|229| float32 fTemp;
|231| fTemp = System.b.c.d.var1;
|232| System.b.c.d.var2 = fTemp;
|233| System.b.c.d.var3 = fTemp;
|234| System.b.c.d.var4 = 0;
|236| fTemp = System.b.c.e.var1;
|237| System.b.c.e.var2 = fTemp;
|238| System.b.c.e.var3 = fTemp;
|239| System.b.c.e.var4 = 0;
|241| fTemp = System.b.c.f.var1;
|242| System.b.c.f.var2 = fTemp;
|243| System.b.c.f.var3 = fTemp;
|244| System.b.c.f.var4 = 0;
|246| fTemp = System.b.c.g.var1;
|247| System.b.c.g.var2 = fTemp;
|248| System.b.c.g.var3 = fTemp;
|249| System.b.c.g.var4 = 0;
|251| fTemp = System.b.c.h.var1;
|252| System.b.c.h.var2 = fTemp;
|253| System.b.c.h.var3 = fTemp;
|254| System.b.c.h.var4 = 0;
}
With CGT 18.2.2, and later tested CGT 20.2.2 and 20.8.0, at optimization level 1 and higher the code generated caused improper program operation. There was also unexpected data write at adresses 0x957E-0x9581. When looked at the generated code, it was obvious that something went wrong with the DP (Data Page) pointer load optimization. Here is listing of assembly generated with CGT 20.8.0 and opt1:
590 0000011b 761F! MOVW DP,#_System+4310 ; [CPU_ARAU]
0000011c 0043
592 0000011d E591 ZERO R1H ; [CPU_FPU] |234|
594 0000011e E223! MOVD32 R0H,@$BLOCKED(_System)+4310 ; [CPU_FPU] |232|
0000011f 0016
596 00000120 E203! MOV32 @$BLOCKED(_System)+4314,R0H ; [CPU_FPU] |233|
00000121 001A
598 00000122 E203! MOV32 @$BLOCKED(_System)+4318,R1H ; [CPU_FPU] |234|
00000123 011E
600 00000124 E223! MOVD32 R0H,@$BLOCKED(_System)+4320 ; [CPU_FPU] |237|
00000125 0020
602 00000126 E203! MOV32 @$BLOCKED(_System)+4324,R0H ; [CPU_FPU] |238|
00000127 0024
604 00000128 E203! MOV32 @$BLOCKED(_System)+4328,R1H ; [CPU_FPU] |239|
00000129 0128
606 0000012a E223! MOVD32 R0H,@$BLOCKED(_System)+4330 ; [CPU_FPU] |242|
0000012b 002A
608 0000012c E203! MOV32 @$BLOCKED(_System)+4334,R0H ; [CPU_FPU] |243|
0000012d 002E
610 0000012e E203! MOV32 @$BLOCKED(_System)+4338,R1H ; [CPU_FPU] |244|
0000012f 0132
611 00000130 761F! MOVW DP,#_System+4352 ; [CPU_ARAU]
00000131 0044
613 00000132 E223! MOVD32 R0H,@$BLOCKED(_System)+4350 ; [CPU_FPU] |247| <=== BUG !
00000133 003E
615 00000134 E203! MOV32 @$BLOCKED(_System)+4354,R0H ; [CPU_FPU] |248|
00000135 0002
617 00000136 E203! MOV32 @$BLOCKED(_System)+4358,R1H ; [CPU_FPU] |249|
00000137 0106
618 00000138 761F! MOVW DP,#_System+4340 ; [CPU_ARAU]
00000139 0043
620 0000013a E223! MOVD32 R0H,@$BLOCKED(_System)+4340 ; [CPU_FPU] |252|
0000013b 0034
622 0000013c E203! MOV32 @$BLOCKED(_System)+4344,R0H ; [CPU_FPU] |253|
0000013d 0038
624 0000013e E203! MOV32 @$BLOCKED(_System)+4348,R1H ; [CPU_FPU] |254|
0000013f 013C
629 00000140 0006 LRETR ; [CPU_ALU]
You can see the "BUG" line. The MOVD32 instruction tries to read +4350 offset but DP was set at the +4352 (previous page in this case).
The System is a large struct located at address 0x8440 (and spans across L0-L3 RAM).
This is the code generated with CGT 20.8.0 and opt0:
591 0000011b 761F! MOVW DP,#_System+4310 ; [CPU_ARAU]
0000011c 0043
592 0000011d E2AF! MOV32 R0H,@$BLOCKED(_System)+4310 ; [CPU_FPU] |231|
0000011e 0016
594 0000011f E203! MOV32 @$BLOCKED(_System)+4312,R0H ; [CPU_FPU] |232|
00000120 0018
596 00000121 E203! MOV32 @$BLOCKED(_System)+4314,R0H ; [CPU_FPU] |233|
00000122 001A
598 00000123 E590 ZERO R0H ; [CPU_FPU] |234|
599 00000124 E203! MOV32 @$BLOCKED(_System)+4318,R0H ; [CPU_FPU] |234|
00000125 001E
601 00000126 E2AF! MOV32 R0H,@$BLOCKED(_System)+4320 ; [CPU_FPU] |236|
00000127 0020
603 00000128 E203! MOV32 @$BLOCKED(_System)+4322,R0H ; [CPU_FPU] |237|
00000129 0022
605 0000012a E203! MOV32 @$BLOCKED(_System)+4324,R0H ; [CPU_FPU] |238|
0000012b 0024
607 0000012c E590 ZERO R0H ; [CPU_FPU] |239|
608 0000012d E203! MOV32 @$BLOCKED(_System)+4328,R0H ; [CPU_FPU] |239|
0000012e 0028
610 0000012f E2AF! MOV32 R0H,@$BLOCKED(_System)+4330 ; [CPU_FPU] |241|
00000130 002A
612 00000131 E203! MOV32 @$BLOCKED(_System)+4332,R0H ; [CPU_FPU] |242|
00000132 002C
614 00000133 E203! MOV32 @$BLOCKED(_System)+4334,R0H ; [CPU_FPU] |243|
00000134 002E
616 00000135 E590 ZERO R0H ; [CPU_FPU] |244|
617 00000136 E203! MOV32 @$BLOCKED(_System)+4338,R0H ; [CPU_FPU] |244|
00000137 0032
619 00000138 E2AF! MOV32 R0H,@$BLOCKED(_System)+4350 ; [CPU_FPU] |246|
00000139 003E
621 0000013a 761F! MOVW DP,#_System+4352 ; [CPU_ARAU]
0000013b 0044
622 0000013c E203! MOV32 @$BLOCKED(_System)+4352,R0H ; [CPU_FPU] |247|
0000013d 0000
624 0000013e E203! MOV32 @$BLOCKED(_System)+4354,R0H ; [CPU_FPU] |248|
0000013f 0002
626 00000140 E590 ZERO R0H ; [CPU_FPU] |249|
627 00000141 E203! MOV32 @$BLOCKED(_System)+4358,R0H ; [CPU_FPU] |249|
00000142 0006
629 00000143 761F! MOVW DP,#_System+4340 ; [CPU_ARAU]
00000144 0043
630 00000145 E2AF! MOV32 R0H,@$BLOCKED(_System)+4340 ; [CPU_FPU] |251|
00000146 0034
632 00000147 E203! MOV32 @$BLOCKED(_System)+4342,R0H ; [CPU_FPU] |252|
00000148 0036
634 00000149 E203! MOV32 @$BLOCKED(_System)+4344,R0H ; [CPU_FPU] |253|
0000014a 0038
636 0000014b E590 ZERO R0H ; [CPU_FPU] |254|
637 0000014c E203! MOV32 @$BLOCKED(_System)+4348,R0H ; [CPU_FPU] |254|
0000014d 003C
643 0000014e 0006 LRETR ; [CPU_ALU]
With this code everything works as expected.
I do not use CLA - I noticed some problems with DP when using global variables in C code when the global is declared in CLA code. This is not the case.
Can someone tell me what is wrong here? Am I doing something wrong or this is a bug in compiler? And one more important question: are other MCUs also affected? I'm also using extensively F28335.
The severity of this problem is very big.
Used compiler options:
"C:/ti/ccsv6/tools/compiler/ti-cgt-c2000_20.8.0.STS/bin/cl2000" -v28 -mt --cla_support=cla0 --float_support=fpu32 --vcu_support=vcu0 -O1 --opt_for_speed=5 --advice:performance=all --define=_INLINE --diag_warning=225 --diag_wrap=off --display_error_number --issue_remarks --abi=coffabi --rpt_threshold=30 --asm_listing --preproc_with_compile --preproc_dependency="sources/<filename.d>"
