I am using the Keil uVision development environment with the GNU tools for a Philips LPC2148. Using the version of GCC currently being shipped with the debugger (3.3.1 or some such thing - it's 2.5 yrs old) I stepped through the branch to _start at the end of my startup assembly file that sets exception vectors, stacks, etc. It bounced around a bit then hit a SWI instruction and decided that was undefined. I loaded up gcc-4.0.2 and now I am seeing SWI as the third instruction of _start. Furthermore, it is SWI 0x00123456 which is really weird. I checked the linker map to verify that it was getting the library from the right place, and things looked reasonable there. In the Keil tools I am using support for calls between ARM and THUMB, compiling THUMB code, and enabling ARM/THUMB interworking. I did not give the linker any additional include path or commands beyond what the Keil tool sets up. I have also tried turning off all the THUMB stuff to do a straight ARM system, but it didn't help. Any suggestions on where to go from here would be greatly appreciated. Rebekah
_start code crashes
Started by ●March 12, 2006
Reply by ●March 12, 20062006-03-12
Rebekah Moser wrote: >I am using the Keil uVision development environment with the GNU tools >for a Philips LPC2148. Using the version of GCC currently being >shipped with the debugger (3.3.1 or some such thing - it's 2.5 yrs >old) I stepped through the branch to _start at the end of my startup >assembly file that sets exception vectors, stacks, etc. It bounced >around a bit then hit a SWI instruction and decided that was >undefined. I loaded up gcc-4.0.2 and now I am seeing SWI >as the third instruction of _start. Furthermore, it is SWI 0x00123456 >which is really weird. I checked the linker map to verify that it was >getting the library from the right place, and things looked reasonable >there. In the Keil tools I am using support for calls between ARM and >THUMB, compiling THUMB code, and enabling ARM/THUMB interworking. I >did not give the linker any additional include path or commands beyond >what the Keil tool sets up. I have also tried turning off all the >THUMB stuff to do a straight ARM system, but it didn't help. Any >suggestions on where to go from here would be greatly appreciated. > > > Reading your post, one assumes that the processor is being caught right at startup by the JTAG debugger. However, this reminds me of a problem I ran into very early in development. I had a bad situation where the program would ABORT, I tried to use the JTAG to find the problem but the JTAG would only connect me to an aborted processor. The problem was this, the JTAG (BDI2000) would reset the CPU, then delay for a short interval and then go through the process of stopping the CPU via the JTAG chain. During the time between the reset inactive and when the JTAG finally "caught" the processor, the CPU had run through a large number of instructions and hit the abort point. This was solved by placing a delay loop in the crt0.S file which forces the CPU to configure the secondary JTAG (LPC2106), then delay. The delay allows the Abatron BDI2000 time to "catch" the CPU via the JTAG. This a snippet of my LPC2106 startup, and representative of the same thing in the LPC2138 which I also use: ============= begin crt0.S ==============... ... JTAG2: .word 0x55400000 PINSELREG: .word 0xe002c004 .size _boot, . - _boot .endfunc // Setup the operating mode & stack. // --------------------------------- .global _start, start, _mainCRTStartup .func _start _start: start: _mainCRTStartup: ; ldr r0, JTAG2 ldr r1, PINSELREG str r0, [r1] // activate secondary JTAG port. ; mov r3, #0x10000 startdelay: subs r3, r3, #1 bne startdelay // give debugger time to catch us. ; ldr r0,=_stack msr CPSR_c,#MODE_UND|I_BIT|F_BIT // Undefined Instruction Mode ============== snip ================== TomW -- Tom Walsh - WN3L - Embedded Systems Consultant http://openhardware.net, http://cyberiansoftware.com "Windows? No thanks, I have work to do..." ----------------
Reply by ●March 13, 20062006-03-13
--- In lpc2000@lpc2..., "Rebekah Moser" <moserr@...> wrote:
> I disassembled the code it jumps to for _start,
> which looks like so:
>
> 0x00000258 E3A00016 MOV R0,#0x00000016
> 0x0000025C E28F10E8 ADD R1,PC,#0x000000E8
> 0x00000260 EF123456 SWI 0x00123456
More info on this - this code comes from crt0.o. It appears that gcc
version 4.0.2 has several crt0 options: crt0.o, rdimon-crt0.o,
rdpmon-crt0.o, and redboot-crt0.o. Not all of them have the offending
SWI instruction in them. What is the difference between these?
Thanks,
Rebekah
Reply by ●March 13, 20062006-03-13
At 12:49 AM 3/14/2006 +0000, Rebekah Moser wrote: >--- In lpc2000@lpc2..., "Rebekah Moser" <moserr@...> wrote: > > I disassembled the code it jumps to for _start, > > which looks like so: > > > > 0x00000258 E3A00016 MOV R0,#0x00000016 > > 0x0000025C E28F10E8 ADD R1,PC,#0x000000E8 > > 0x00000260 EF123456 SWI 0x00123456 > >More info on this - this code comes from crt0.o. It appears that gcc >version 4.0.2 has several crt0 options: crt0.o, rdimon-crt0.o, >rdpmon-crt0.o, and redboot-crt0.o. Not all of them have the offending >SWI instruction in them. What is the difference between these? Those are all for different boards (some with built-in monitors) and since you are asking in an LPC group it's likely that none are appropriate. You need startup specific to the LPC to deal with its memory map and any other init you want to occur before the main C code, just as you would for any other microcontroller. There are multiple examples around. I think there are some in the groups files section. Also take a look at the newlib-lpc stuff at http://www.aeolusdevelopment.com/Articles/download.html although that's set up for newlib and the distribution you are using appears to be using a different library. You might also want to take a look at the WINARM distribution which includes the newlib-lpc stuff. There is also the Crossworks distribution which includes a number of other items. Robert
Reply by ●March 13, 20062006-03-13
At 12:49 AM 3/14/2006 +0000, Rebekah Moser wrote: >--- In lpc2000@lpc2..., "Rebekah Moser" <moserr@...> wrote: > > I disassembled the code it jumps to for _start, > > which looks like so: > > > > 0x00000258 E3A00016 MOV R0,#0x00000016 > > 0x0000025C E28F10E8 ADD R1,PC,#0x000000E8 > > 0x00000260 EF123456 SWI 0x00123456 > >More info on this - this code comes from crt0.o. It appears that gcc >version 4.0.2 has several crt0 options: crt0.o, rdimon-crt0.o, >rdpmon-crt0.o, and redboot-crt0.o. Not all of them have the offending >SWI instruction in them. What is the difference between these? Those are all for different boards (some with built-in monitors) and since you are asking in an LPC group it\'s likely that none are appropriate. You need startup specific to the LPC to deal with its memory map and any other init you want to occur before the main C code, just as you would for any other microcontroller. There are multiple examples around. I think there are some in the groups files section. Also take a look at the newlib-lpc stuff at http://www.aeolusdevelopment.com/Articles/download.html although that\'s set up for newlib and the distribution you are using appears to be using a different library. You might also want to take a look at the WINARM distribution which includes the newlib-lpc stuff. There is also the Crossworks distribution which includes a number of other items. Robert
Reply by ●March 13, 20062006-03-13
At 12:49 AM 3/14/2006 +0000, Rebekah Moser wrote: >--- In lpc2000@lpc2..., "Rebekah Moser" <moserr@...> wrote: > > I disassembled the code it jumps to for _start, > > which looks like so: > > > > 0x00000258 E3A00016 MOV R0,#0x00000016 > > 0x0000025C E28F10E8 ADD R1,PC,#0x000000E8 > > 0x00000260 EF123456 SWI 0x00123456 > >More info on this - this code comes from crt0.o. It appears that gcc >version 4.0.2 has several crt0 options: crt0.o, rdimon-crt0.o, >rdpmon-crt0.o, and redboot-crt0.o. Not all of them have the offending >SWI instruction in them. What is the difference between these? Those are all for different boards (some with built-in monitors) and since you are asking in an LPC group it\\\'s likely that none are appropriate. You need startup specific to the LPC to deal with its memory map and any other init you want to occur before the main C code, just as you would for any other microcontroller. There are multiple examples around. I think there are some in the groups files section. Also take a look at the newlib-lpc stuff at http://www.aeolusdevelopment.com/Articles/download.html although that\\\'s set up for newlib and the distribution you are using appears to be using a different library. You might also want to take a look at the WINARM distribution which includes the newlib-lpc stuff. There is also the Crossworks distribution which includes a number of other items. Robert
