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CH32V: Reorganize startup logic #881

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CH32V: Reorganize startup logic #881

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dd7a87c
like this?
piotrfila Jan 25, 2026
94b30bb
tail call _system_init
piotrfila Jan 25, 2026
4e95302
make diff nicer
piotrfila Jan 25, 2026
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27 changes: 12 additions & 15 deletions port/wch/ch32v/src/cpus/main.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -220,21 +220,25 @@ pub const startup_logic = struct {
extern fn microzig_main() noreturn;

pub fn _start() callconv(.naked) void {
// Set global pointer.
asm volatile (
\\
// Set global pointer.
\\.option push
\\.option norelax
\\la gp, __global_pointer$
\\.option pop
);
\\
// Set stack pointer.
\\mv sp, %[eos]

// Set stack pointer.
const eos = comptime microzig.utilities.get_end_of_stack();
asm volatile ("mv sp, %[eos]"
// Initialize the system.
\\j _system_init
:
: [eos] "r" (@as(u32, @intFromPtr(eos))),
: [eos] "r" (comptime microzig.utilities.get_end_of_stack()),
);
}

export fn _system_init() callconv(.c) noreturn {
// NOTE: this can only be called once. Otherwise, we get a linker error for duplicate symbols
startup_logic.initialize_system_memories();

Expand Down Expand Up @@ -278,11 +282,7 @@ pub const startup_logic = struct {
.mpp = 0x3,
});

// Initialize the system.
@export(&startup_logic._system_init, .{ .name = "_system_init" });
asm volatile (
\\jal _system_init
);
cpu_impl.system_init(microzig.chip);

// Load the address of the `microzig_main` function into the `mepc` register
// and transfer control to it using the `mret` instruction.
Expand All @@ -295,6 +295,7 @@ pub const startup_logic = struct {
// machine mode and we are switching to machine mode, but normally this could switch us to
// user mode.
asm volatile ("mret");
unreachable;
}

inline fn initialize_system_memories() void {
Expand Down Expand Up @@ -327,10 +328,6 @@ pub const startup_logic = struct {
);
}

fn _system_init() callconv(.c) void {
cpu_impl.system_init(microzig.chip);
}

export fn _reset_vector() linksection("microzig_flash_start") callconv(.naked) void {
asm volatile ("j _start");
}
Expand Down
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