Which tool to use to write ARM assembler with c code and compile the same?
If I understand correctly, you want to mix Arm assembly code with C code and call those assembly functions from C, right?
You can do this with any compiler and assembler that targets the Arm architecture. For example, Arm Development Studio (Arm DS) includes Arm Compiler 6, armclang. The armclang compiler includes an integrated assembler.
For more information about how to call assembly functions from C, see the Arm Compiler documentation: https://developer.arm.com/documentation/100748/0616/Using-Assembly-and-Intrinsics-in-C-or-C---Code/Calling-assembly-functions-from-C-and-C--
To download an evaluation copy of Arm Development Studio, see here: https://developer.arm.com/tools-and-software/embedded/arm-development-studio
Hope that helps,
What device are you planning to write code on?
If it is a Cortex-M based-device, you might also look at https://www.keil.com/ a toolset optimized for writing code on Cortex-M devices
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