newlib | Newlib for aarch64-darwin

Update: Writing this out allowed me to spot where I was going wrong, but not why. I am obviously calling fgets in the wrong way, because after five calls I get to the address 0x221000 which is where the mmapped memory is - I am writing at higher addresses - but I don't know why that that is happening. Could someone explain?

This is a bit complex and I'm at a loss to see why this behaviour is seen: I don't know if I have got the basics wrong or if it's a feature of Spike/PK.

To note: the libc here is provided by newlib and the code is compiled as riscv64-unknown-elf.

Short version I have input code written in RISC-V assembly that previously ran smoothly, but since I introduced a system call to mmap it crashes the fifth time it is executed. Is the problem because I have got the wrong sequence of calls or possibly an issue with the Spike emulator and PK proxy kernel?

Long explanation

I am writing a Forth-like threaded interpreted language. It is currently targeted at the PK proxy kernel on the Spike emulator, but hopefully soon to run on 'real' hardware. The code is at https://github.com/mcmenaminadrian/riscyforth

The TIL implements an endless loop to pick up input calling, in sequence, a routine to get the filepointer for standard input and then a routine to get the input.

To get the standard input filepointer (which is stored on the stack):

let me start by saying that this is my first time really meddling with GCC, so I apologize if this question is not very constructive or has been answered before.

I have two static libraries:

"L1.h"

I would like to create a build of my embedded C code which specifically checks that floating point operations aren't introduced into it by accident. I've tried adding +nofp to my [cortex-m3] processor architecture but GCC for ARM doesn't like that (probably because the cortex-m3 doesn't have a floating point unit). I've tried specifying -mfpu=none but that isn't a permitted option. I've tried leaving -lm off the linker command-line but the linker seems too clever to be fooled by that and is compiling code with double in it and resolving pow() anyway.

This post: https://gcc.gnu.org/legacy-ml/gcc-help/2011-07/msg00093.html from 2011 hints that GCC has no such option, since no-one is interested in it, which surprises me as it seems like a common thing to want, at least from an embedded standpoint, to avoid accidental C-library bloat.

Does anyone know of a way to do this with GCC/newlib without me having to go through and manually hack stuff out of the C library file it chooses?

I have a target (Stm32f030R8) I am using with FreeRTOS and the newlib reentrant heap implementation (http://www.nadler.com/embedded/newlibAndFreeRTOS.html). This shim defines sbrk in addition to implementing the actual FreeRTOS memory allocation shim. The project is built with GNU ARM GCC and using --specs=nosys.specs.

For the following example, FreeRTOS has not been started yet. malloc has not been called before. The mcu is fresh off boot and has only just copied initialized data from flash into ram and configured clocks and basic peripherals.

Simply having the lib in my project, I am seeing that sbrk is being called with very large increment values for seemingly small malloc calls.

The target has 8K of memory, of which I have 0x12b8 (~4KB bytes between the start of the heap and end of ram (top of the stack).

I am seeing that if I allocate 1000 bytes with str = (char*) malloc(1000);, that sbrk gets called twice. First with an increment value of 0x07e8 and then again with an increment value of 0x0c60. the result being that the desired total increment count is 0x1448 (5192 bytes!) and of course this overflows not just the stack, but available ram.

What on earth is going on here? Why are these huge increment values being used by malloc for such a relatively small desired buffer allocation?

I want to get some output on a RISC-V program (assembly) running on top of pk on Spike using newlib.

I can call printf with null terminated strings eg (snippet)

I am compiling newlib so I can continue the building of my cross-compiler, but newlib is getting confused with the 32-bit support I also included in my cross-compiler.

I already have my cross-compiler compiled and installed, but it's missing a standard library along with libgcc, so most programs will not compile, but programs not using standard functions will compile as long as the -nostdlib argument is used

If you're asking to me: "You should use glibc instead!", I'll answer: It requires source files from Linux, but the Linux source code does not play well on Windows, because Windows thinks that some files are the same due to the case-insensitive file system.

The errors are:

I wanted to use the cross-compiler for some testing on an or1200 design in which I used to perform some benchmarks on another machine. The other machine had the binaries of the or32-uclinux- tool chain and I coppied those to my Ubuntu 20.04 machine.

The binaries seem to work fine, but when I tried to compile my assembly code with

i'm new in this type of coding and i'm trying to do some test executing bare-metal software for Cortex-A processors. I have experience with Cortex-M MCU and i compiled code with an IDE like ARM-Keil and with SDK by Nordic for some BLE jobs. Now i want to try to understand better the world of Cortex-A and i would learn coding in a bare-metal way, starting from some examples that i found online. I had some experiences with freeRTOS with Cortex-M, so i found online some git repository from some good guy that makes a porting of freeRTOS for RaspberryPI and BeableBoneBlack. From now on i will just explain my problem for the BeableBoneBlack, beacouse for the RaspberryPI it's similar.

I'm on linux, i installed gcc-arm-none-eabi compiler, so i cloned the BeagleBone Black with freeRTOS repository from this link.

I usually use VS Code to write code, so in the integrated terminal when i run the command make everything it's working and the of my BBB flashes correctly. So now i would like to improve my code, and in order to do some tests i would like to use the rand() function, from stdlib.h. Unhappily I find that there are some errors: undefined reference to rand. The last months, before doing tests with the BBB, i found other repos for RPi2 and i learn something about the linker of the arm-none-eabi compiler, that needs the addition of some parameters in order link library files during the process. From this repo now i have two files: makedefs_ti and makefile. Opening the make file i found in line 26-27 the part of the generation of the file app, so where the linker is called. In this lines there are references to LIB_GCC and LIB_C, which are defined in the makedefs_ti. In lines 49-50 there are the references to the directory where the compiler is installed (I changed 4.7.3 with the correct one installed on my linux pc that is 9.2.1). In the makefile, after -L$(LIB_C), if i add the linker parameters like -lc or -lg and try to recompile, i had error like arm-none-eabi-ld: cannot find -lc. With some understanding from online resources i modified the the makedefs_ti as following:

I am trying to write a simple "Hello, World!" firmware for Cortex-M0 CPU. The goal is to correctly initialize and shutdown C++ runtime so that global constructors are called before main() and global destructors are called after main(). So far I managed to get exactly half of it working - global ctors run correctly, but global destructors don't. I use gcc on Windows with the Newlib, which is supposed to initialize the runtime.