[fpc-devel] Code generated for the embedded arm port for lpc1768 (armv7m)

[Michael Ring]

I remember seeing the problem that gdb does not correctly disassemble 
code...

Please do a

  arm-none-eabi-readelf -A xxx.elf

you should see:

File Attributes
   Tag_CPU_name: "7-M"
   Tag_CPU_arch: v7
   Tag_CPU_arch_profile: Microcontroller
   Tag_THUMB_ISA_use: *Thumb-2*

Compiling, linking and running is fine for me, difference in setup is 
that I use another processor (stm32f407) and that I used trunk sources 
to compile the crosscompiler.
But as Jeppe already mentioned, this all should have worked fine with 
2.6.4 version too.

And your commandline you used for both creating the crosscompiler / 
build the program is exactly the same I use.

Michael

Am 23.10.14 um 20:15 schrieb Sietse Achterop:
>   Hello,
> I am trying to get the embedded version of fpc for arm to work.
> Currently i try it for the lpc1768 from NXP using the lpcxpresso board.
> The example compiles, but doesn't run on the target...
>
> I created a simple example and it seems that the code it generates is 
> NOT thumb2 code.
> I disassembled the elf-file generated by fpc using 
> "arm-none-eabi-objdump -S"
> I also disassembled it using the debugger "arm-none-eabi-gdb"
> Here is a fragment of the code from both:
>
> From objdump:
> 000001c4 <FPC_INITIALIZEUNITS>:
>  1c4:    e92d4070     push    {r4, r5, r6, lr}
>  1c8:    ebfffff5     bl    1a4 <SYSTEM_$$_FPC_CPUINIT>
>  1cc:    e59f006c     ldr    r0, [pc, #108]    ; 240 
> <FPC_INITIALIZEUNITS+0x7c>
>  1d0:    e5904000     ldr    r4, [r0]
>  1d4:    e3a05001     mov    r5, #1
>  1d8:    e1540005     cmp    r4, r5
>  1dc:    ba00000f     blt    220 <FPC_INITIALIZEUNITS+0x5c>
>
> From gdb
>    0x000001c4 <fpc_initializeunits+0>:        70 40 eors             
> r0, r6
>    0x000001c6 <fpc_initializeunits+2>:        2d e9 f5 ff             
> stmdb    sp!, {r0, r2, r4, r5, r6, r7, r8, r9, r10, r11, r12, sp, lr, pc}
> => 0x000001ca <fpc_initializeunits+6>:        ff eb 6c 
> 00                          ; <UNDEFINED> instruction: 0xebff006c
>    0x000001ce <fpc_initializeunits+10>:        9f e5 
> b.n                     0xfffffd10
>    0x000001d0 <fpc_initializeunits+12>:        00 40 
> ands                     r0, r0
>    0x000001d2 <fpc_initializeunits+14>:        90 e5 
> b.n                     0xfffffcf6
>    0x000001d4 <fpc_initializeunits+16>:        01 50 
> str                     r1, [r0, r0]
>    0x000001d6 <fpc_initializeunits+18>:        a0 e3 
> b.n                     0x91a
>    0x000001d8 <fpc_initializeunits+20>:        05 00 
> movs                     r5, r0
>    0x000001da <fpc_initializeunits+22>:        54 e1 
> b.n                     0x486
>    0x000001dc <fpc_initializeunits+24>:        0f 00 
> movs                     r7, r1
>
> Note how the interpretation of the code is different, as is the length 
> of most instructions.
> It looks to me as if the code in the elf-file are (mostly) 32-bit 
> values, while the debugger does interpret thee code as thumb2 (i think).
>
> In the Makefile in rtl/embedded I find:
>
>     ifeq ($(SUBARCH),armv7m)
>     CPU_UNITS=lm3fury lm3tempest stm32f10x_ld stm32f10x_md 
> stm32f10x_hd stm32f10x_xl stm32f10x_conn stm32f10x_cl lpc13xx lpc1768 
> lm4f120  xmc4500 cortexm3 cortexm4 # thumb2_bare
>     endif
>
> So that suggest (via the comment) that fpc can do thumb2 code, which 
> it should for cortexm3.
>
> My PC is debian/jessie/64bit:  Free Pascal Compiler version 
> 2.6.4+dfsg-3 [2014/07/12] for x86_64
> I got the sourcecode for the port from svn as described on the website.
> To create the port I do:
>
>     make clean buildbase installbase CROSSINSTALL=1 OS_TARGET=embedded 
> CPU_TARGET=arm SUBARCH=armv7m BINUTILSPREFIX=arm-none-eabi-
>
> For the binutils I use the (current) stuff for the lpc1768 from NXP: 
> lpcxpresso_7.4.0_229
>
> To create a program I do:
>
>     ppcrossarm -Ch1024 -Cs1024 -Tembedded -Parm -Cparmv7m 
> -XParm-none-eabi- -Wplpc1768 -vu prog.p
>
> Is there anybody that did get this port to work?
>
>   Thanks in advance,
>        Sietse
>
>
>
> _______________________________________________
> fpc-devel maillist  -  fpc-devel at lists.freepascal.org
> http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-devel

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