unique viper
I am trying to initialize vector_table for AVR. For that purpose the next code is used:
export const vector_table linksection(".vectors") = blk: {
// do some checks
var asm_str: []const u8 = "jmp _start\n";
// do some more stuff
asm_str = asm_str ++ new_insn ++ "\n";
break blk: asm (asm_str);
}
Zig infers the type of break expression to void. Compilation fails with:
src/start.zig:7:1: error: unable to export type 'void'
So how it should be done it the right way?
it seems that it is impossible to export container scoped assembly
as return type of asm () container level expression is void
Ok, as I have taken this code from github, it seems that it is outdated and I should use @export instead
So, it seems that avr is quite broken, as compilation fails due to internal error
/usr/lib/zig/lib/std/builtin.zig:861:9: error: expected type 'fn([]const u8, ?*builtin.StackTrace, ?usize) noreturn', found 'fn([]const u8, ?*builtin.StackTrace) noreturn'
zig version: 0.11.0-dev.3312+ab37ab33c
ebon trellis
is that the complete error? To me that looks like you're setting the panic function to something with the wrong type
unique viper
full output
zig build-exe avr-arduino-zig Debug native: error: the following command failed with 1 compilation errors:
/usr/lib/zig/zig build-exe /home/username/programming/projects/remote/avr-arduino-zig/src/start.zig -femit-asm --cache-dir /home/username/programming/projects/remote/avr-arduino-zig/zig-cache --global-cache-dir /home/username/.cache/zig --name avr-arduino-zig -fno-compiler-rt -target avr-freestanding-none -mcpu atmega328p --script /home/username/programming/projects/remote/avr-arduino-zig/src/linker.ld --listen=-
Build Summary: 0/3 steps succeeded; 1 failed (disable with -fno-summary)
install transitive failure
├─ install avr-arduino-zig transitive failure
│ └─ zig build-exe avr-arduino-zig Debug native 1 errors
└─ zig build-exe avr-arduino-zig Debug native (reused)
/usr/lib/zig/lib/std/builtin.zig:861:9: error: expected type 'fn([]const u8, ?*builtin.StackTrace, ?usize) noreturn', found 'fn([]const u8, ?*builtin.StackTrace) noreturn'
root.panic
~~~~^~~~~~
/usr/lib/zig/lib/std/builtin.zig:861:9: note: function with 2 parameters cannot cast into a function with 3 parameters
referenced by:
addFeature: /usr/lib/zig/lib/std/target.zig:719:21
featureSet: /usr/lib/zig/lib/std/target.zig:781:30
remaining reference traces hidden; use '-freference-trace' to see all reference traces
ok, so for some strange reason error message hasn't mentioned where exactly error came from, but I guess I have figured it out
So, I have solved the problem with panic
the issue with asm is still relevant though
how can I see the vervose output of build command. option verbose does not seems to work as I expect (it prints only command executed, not their error output)
unique viper
it seems that zig build crashes itself
Perhaps I need to compile zig from source code in debug mode to see more verbose error message
hoary citrus
this isn't container scoped, you're just trying to return void from a comptime block it looks like
wrap the block in asm like asm(blk: { <your code> break :blk code; }) and I don't see why it wouldn't work?
what your code is trying to do is evaluate the assembly at comptime which doesn't make any sense
unique viper
https://github.com/owl-from-hogvarts/avr-arduino-zig
checkout src/start.zig file
the original code is not mine, and I haven't understood it fully yet
unique viper
this isn't container scoped, you're just trying to return void from a comptime b...
notice that asm expression has void type, because it actually returns nothing. Also the variable is unused withing zig code. Thus I may assume that the only reason for it to exist is to link the asm to .vectors table
ok, I have updated the compiler to most recent commit and it seems to report error messages correctly now
though still requires more investigation
unique viper
it seems to compile correctly now
one more question, is how to disable memcpy and other std functions being emmited into assembly
here the deploy happens to bare metal, so there are no such functions present
in C there is a flag -fno-builtin which disables these functions
zig does not udnerstand it
although freestanding is set in build.zig, this still does not help much
