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+/* LoongArch support code for fibers and multithreading.
+ Copyright (C) 2023 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+for more details.
+
+Under Section 7 of GPL version 3, you are granted additional
+permissions described in the GCC Runtime Library Exception, version
+3.1, as published by the Free Software Foundation.
+
+You should have received a copy of the GNU General Public License and
+a copy of the GCC Runtime Library Exception along with this program;
+see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+<http://www.gnu.org/licenses/>. */
+
+#include "../common/threadasm.S"
+
+/**
+ * Performs a context switch.
+ *
+ * $a0 - void** - ptr to old stack pointer
+ * $a1 - void* - new stack pointer
+ *
+ */
+
+#if defined(__loongarch_lp64)
+# define GPR_L ld.d
+# define GPR_S st.d
+# define SZ_GPR 8
+# define ADDSP(si) addi.d $sp, $sp, si
+#elif defined(__loongarch64_ilp32)
+# define GPR_L ld.w
+# define GPR_S st.w
+# define SZ_GPR 4
+# define ADDSP(si) addi.w $sp, $sp, si
+#else
+# error Unsupported GPR size (must be 64-bit or 32-bit).
+#endif
+
+#if defined(__loongarch_double_float)
+# define FPR_L fld.d
+# define FPR_S fst.d
+# define SZ_FPR 8
+#elif defined(__loongarch_single_float)
+# define FPR_L fld.s
+# define FPR_S fst.s
+# define SZ_FPR 4
+#else
+# define SZ_FPR 0
+#endif
+
+ .text
+ .align 2
+ .global fiber_switchContext
+ .type fiber_switchContext, @function
+fiber_switchContext:
+ .cfi_startproc
+ ADDSP(-11 * SZ_GPR)
+
+ // fp regs and return address are stored below the stack
+ // because we don't want the GC to scan them.
+
+ // return address (r1)
+ GPR_S $r1, $sp, -SZ_GPR
+
+#if SZ_FPR != 0
+ // callee-saved scratch FPRs (f24-f31)
+ FPR_S $f24, $sp, -SZ_GPR-1*SZ_FPR
+ FPR_S $f25, $sp, -SZ_GPR-2*SZ_FPR
+ FPR_S $f26, $sp, -SZ_GPR-3*SZ_FPR
+ FPR_S $f27, $sp, -SZ_GPR-4*SZ_FPR
+ FPR_S $f28, $sp, -SZ_GPR-5*SZ_FPR
+ FPR_S $f29, $sp, -SZ_GPR-6*SZ_FPR
+ FPR_S $f30, $sp, -SZ_GPR-7*SZ_FPR
+ FPR_S $f31, $sp, -SZ_GPR-8*SZ_FPR
+#endif
+
+ // callee-saved GPRs (r21, fp (r22), r23-r31)
+ GPR_S $r21, $sp, 0*SZ_GPR
+ GPR_S $fp, $sp, 1*SZ_GPR
+ GPR_S $s0, $sp, 2*SZ_GPR
+ GPR_S $s1, $sp, 3*SZ_GPR
+ GPR_S $s2, $sp, 4*SZ_GPR
+ GPR_S $s3, $sp, 5*SZ_GPR
+ GPR_S $s4, $sp, 6*SZ_GPR
+ GPR_S $s5, $sp, 7*SZ_GPR
+ GPR_S $s6, $sp, 8*SZ_GPR
+ GPR_S $s7, $sp, 9*SZ_GPR
+ GPR_S $s8, $sp, 10*SZ_GPR
+
+ // swap stack pointer
+ GPR_S $sp, $a0, 0
+ move $sp, $a1
+
+ GPR_L $r1, $sp, -SZ_GPR
+
+#if SZ_FPR != 0
+ FPR_L $f24, $sp, -SZ_GPR-1*SZ_FPR
+ FPR_L $f25, $sp, -SZ_GPR-2*SZ_FPR
+ FPR_L $f26, $sp, -SZ_GPR-3*SZ_FPR
+ FPR_L $f27, $sp, -SZ_GPR-4*SZ_FPR
+ FPR_L $f28, $sp, -SZ_GPR-5*SZ_FPR
+ FPR_L $f29, $sp, -SZ_GPR-6*SZ_FPR
+ FPR_L $f30, $sp, -SZ_GPR-7*SZ_FPR
+ FPR_L $f31, $sp, -SZ_GPR-8*SZ_FPR
+#endif
+
+ GPR_L $r21, $sp, 0*SZ_GPR
+ GPR_L $fp, $sp, 1*SZ_GPR
+ GPR_L $s0, $sp, 2*SZ_GPR
+ GPR_L $s1, $sp, 3*SZ_GPR
+ GPR_L $s2, $sp, 4*SZ_GPR
+ GPR_L $s3, $sp, 5*SZ_GPR
+ GPR_L $s4, $sp, 6*SZ_GPR
+ GPR_L $s5, $sp, 7*SZ_GPR
+ GPR_L $s6, $sp, 8*SZ_GPR
+ GPR_L $s7, $sp, 9*SZ_GPR
+ GPR_L $s8, $sp, 10*SZ_GPR
+
+ ADDSP(11 * SZ_GPR)
+
+ jr $r1 // return
+ .cfi_endproc
+ .size fiber_switchContext,.-fiber_switchContext