I don't have time to produce an isolated example case right now (I can later this week), but I hope it's obvious enough that someone might be able to figure out what's going on.
I have the following serial port code:
int16_t SerialPort::getByte(uint32_t timeout)
{
char rxChar;
if(rxQueue.receive(&rxChar, timeout / 1000))
{
receivedBytes++;
return (int16_t)rxChar;
}
else
return -1;
}
This produces the following assembly (error in bold):
E92D500F STMFD R13!, {R0, R1, R2, R3, R12, R14}
EEF1CA10 FMXR R12, FPSCR
E92D1000 STMFD R13!, {R12}
E58D1004 STR R1, [R13, #4]
E58D0000 STR R0, [R13]
E59D0004 LDR R0, [R13, #4]
E3A01FFA MOV R1, #1000
EB0010B8 BL __aeabi_uidivmod
E59DC000 LDR R12, [R13]
E1A02000 MOV R2, R0
E28D1008 ADD R1, R13, #8
E28C000C ADD R0, R12, #12
EB001284 BL receive
E3500000 CMP R0, #0
0A000004 BEQ $C$L15
E59DC000 LDR R12, [R13]
E59C0024 LDR R0, [R12, #36]
E2800001 ADD R0, R0, #1
E58C0024 STR R0, [R12, #36]
EA000001 B $C$L16
$C$L15:
E3A0C0FF MOV R12, #255
E5CDC008 STRB R12, [R13, #8]
$C$L16:
E5DD0008 LDRB R0, [R13, #8]
E58D0000 STR R0, [R13]
E8BD1000 LDMFD R13!, {R12}
E8BD900F LDMFD R13!, {R0, R1, R2, R3, R12, PC}
The notable error here is that the function prolog and epilog save and restore r0, which according to ABI is the return value. Before r0 is popped from the stack, it contains the return value I'd expect; afterwards it contains the first function argument, which is the value it held when it entered the function.
The serial port file is compiled with the following flags:
cl470 -mv7R4 -g <includes> --diag_warning=225 --enum_type=packed --elf --abi=eabi --code_state=32 --float_support=VFPv3D16 --preproc_with_compile --preproc_dependency="serial_port.pp" --obj_directory="<objs>" "serial_port.cpp"
I'm using CCS 4.2.4.00033 on Windows XP, developing for the TMS570 architecture.
This is blocking development for me at the moment, and the severity of this error is obvious.
Thanks,
Tom
