I compile mote using sky mote in contiki, it works well. But when I use Z1 mote,it report an error:
Assembler messages:
Error: odd operand: 11
How to solve it?
Related
a=1
% Construct the trasfer function
num=[a 1 3]
den=[1 2 10]
G=tf(num,den)
% Impulse response
impulse(G)
% Step response
step(G)
When I click on 'run' this error appears "error: Order numerator >= order denominator"
If you follow the error on the terminal, it suggests that line 95 in imp_invar.m of the control package is to blame. (if you don't know where this was installed, you can find out by typing pkg list in your terminal)
If you convert this error to a warning, the code continues. Obviously you do so at your own risk. I would make a backup of the original .m file just in case.
Note that the same code run on matlab does not issue any error or warning (which is odd in itself, given the stark note about invalid impulse invariance in this scenario from octave ... there is a reference quoted inside imp_invar.m if you're interested.)
I am trying to install the SpinWheelControl Cocoapod: https://github.com/joshdhenry/SpinWheelControl using swift 5 and Xcode 10.3. Installation is fine but when I go to run, the compiler gives an error:
"The compiler is unable to type-check this expression in reasonable time; try breaking up the expression into distinct sub-expressions"
at this line of code:
let nearestWedge: Int = Int(round(((currentRadians + (radiansPerWedge / 2)) + snappingPositionRadians) / radiansPerWedge))
This type of wheel would be really useful for me if it worked.
Are you able to get this framework running with Swift 5 or perhaps refactor that line of code so it will run?
Thank you!
Try to break the single long expression into small expressions.
For example :
let exp1 = currentRadians + (radiansPerWedge / 2)
let exp2 = (exp1 + snappingPositionRadians) / radiansPerWedge
let nearestWedge = Int(round(exp2))
I get linking problem when create library for iOS 7 on iPhone (ARM64).
The error message is:
ld: in /long_path/libHEVCCodec.a(inv_xforms_arm64.o), in section TEXT,text reloc 0:
ARM64_RELOC_SUBTRACTOR must have r_length of 2 or 3 for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
This error appears as a result to this code (it's some sort of switch):
adr addr, .L.dct_add_switch
ldrh offset, [addr, ta, lsl #1]
add addr, addr, offset, uxth
br addr
.L.dct_add_switch:
.hword .L.dct_add_4 - .L.dct_add_switch
.hword .L.dst_add_4 - .L.dct_add_switch
...
ta, addr, offset are general registers x3, x4, w5 respectively.
Does anybody know how to handle this situation?
PS: there are not any problems with GNU GCC & Android.
EDIT1:
It seems that problem is not in linker itself but in compiler.
I checked object file (objdump) and instead of difference constants there are just zeros.
.L.dct_add_switch:
0000000000000010 .long 0x00000000
0000000000000014 .long 0x00000000
0000000000000018 .long 0x00000000
000000000000001c nop
When I put manually calculated constants instead of ".L.dct_add_4 - .L.dct_add_switch", etc expressions, everything is going all right.
Maybe there is some compiler keys which will make compiler to do it job rightfully?
Thanks.
Well there is a compiler & linker problem and it depends on the size of data which are used for offsets. Clang is not very friendly to anything what is different from 4 Bytes.
The discussion and possible solutions in other topic: creating constant jump table; xcode; clang; asm
The problem is the Mach-O object file format for ARM 64-bit targets doesn't support a relocation for the 16-bit difference between two symbols. It appears that the difference must be 32-bit or 64-bit. It doesn't seem to be a problem with the compiler or the linker. The assembly code you've quoted in your question looks like handcrafted assembly, not compiler output.
The solution would be to rewrite the assembly to use 32-bit difference values. Something like this:
adr addr, .L.dct_add_switch
ldr offset, [addr, ta, lsl #2]
add addr, addr, offset, uxtw
br addr
.L.dct_add_switch:
.word .L.dct_add_4 - .L.dct_add_switch
.word .L.dst_add_4 - .L.dct_add_switch
I have an AArch64 NEON function defined in an assembly .s file. It's already compiling and running fine, but to improve code readability I'd like to use register aliases with the .req assembler directive. Although when I try to do it clang fails with error: unexpected token in argument list
To keep the example simple consider this code:
.section __TEXT,__text,regular,pure_instructions
.globl _foo
.align 2
_foo:
add w0, w0, w1
ret lr
This code compiles and runs, but if I try to use
myreg .req w0
before the add instruction, I get
/Users/dfcamara/Desktop/MyApp/MyApp/foo.s:5:16: error: unexpected token in argument list
myreg .req w0
^
Maybe I need some clang directive that I'm not aware, I can't find documentation about them. Or a compiler option. I just created a new iOS (iPad) project and added an assembly file.
Thanks
I am trying to follow another SO post and implement sqrt14 within my iOS app:
double inline __declspec (naked) __fastcall sqrt14(double n)
{
_asm fld qword ptr [esp+4]
_asm fsqrt
_asm ret 8
}
I have modified this to the following in my code:
double inline __declspec (naked) sqrt14(double n)
{
__asm__("fld qword ptr [esp+4]");
__asm__("fsqrt");
__asm__("ret 8");
}
Above, I have removed the "__fastcall" keyword from the method definition since my understanding is that it is for x86 only. The above gives the following errors for each assembly line respectively:
Unexpected token in argument list
Invalid instruction
Invalid instruction
I have attempted to read through a few inline ASM guides and other posts on how to do this, but I am generally just unfamiliar with the language. I know MIPS quite well, but these commands/registers seem to be very different. For example, I don't understand why the original author never uses the passed in "n" value anywhere in the assembly code.
Any help getting this to work would be greatly appreciated! I am trying to do this because I am building an app where I need to calculate sqrt (ok, yes, I could do a lookup table, but for right now I care a lot about precision) on every pixel of a live-video feed. I am currently using the standard sqrt, and in addition to the rest of the computation, I'm running at around 8fps. Hoping to bump that up a frame or two with this change.
If it matters: I'm building the app to ideally be compatibly with any current iOS device that can run iOS 7.1 Again, many thanks for any help.
The compiler is perfectly capable of generating fsqrt instruction, you don't need inline asm for that. You might get some extra speed if you use -ffast-math.
For completeness' sake, here is the inline asm version:
__asm__ __volatile__ ("fsqrt" : "=t" (n) : "0" (n));
The fsqrt instruction has no explicit operands, it uses the top of the stack implicitly. The =t constraint tells the compiler to expect the output on the top of the fpu stack and the 0 constraint instructs the compiler to place the input in the same place as output #0 (ie. the top of the fpu stack again).
Note that fsqrt is of course x86-only, meaning it wont work for example on ARM cpus.