// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
// SPDX-License-Identifier: BSD-3-Clause

#include "textflag.h"

// ABI0 JIT trampoline for LoongArch 64.
//
// enterJIT saves Go SP and RA (R1), switches to the prepared stack, and
// jumps to the JIT function.  When the function RETs (JIRL zero, ra, 0),
// control lands in leaveJIT.

// func enterJIT(fn uintptr, stack uintptr)
TEXT ·enterJIT(SB), NOSPLIT, $0-16
	MOVV fn+0(FP), R4           // target function address (A0)
	MOVV R1, savedRA(SB)        // save return address (RA)
	MOVV R3, savedSP(SB)        // save Go stack pointer (SP)
	MOVV stack+8(FP), R5        // load prepared stack pointer (A1)
	MOVV 0(R5), R1              // load leaveJIT address into RA
	ADDV $8, R5, R5             // advance past return address
	MOVV R5, R3                 // switch to prepared stack (SP)
	JIRL R0, R4, 0              // jump to JIT function

// func leaveJIT()
TEXT ·leaveJIT(SB), NOSPLIT, $0-0
	MOVV savedSP(SB), R5        // restore Go stack pointer
	MOVV R5, R3                 // restore SP
	MOVV savedRA(SB), R1        // restore return address
	JIRL R0, R1, 0              // return to Go caller

GLOBL savedRA(SB), NOPTR, $8
GLOBL savedSP(SB), NOPTR, $8