From 89536b198d4688fbe86d8f213831504b5e2855c5 Mon Sep 17 00:00:00 2001 From: Ariadne Conill Date: Sun, 6 Dec 2020 00:04:50 -0600 Subject: [PATCH] m68k: add swapcontext --- arch/m68k/swapcontext.S | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) create mode 100644 arch/m68k/swapcontext.S diff --git a/arch/m68k/swapcontext.S b/arch/m68k/swapcontext.S new file mode 100644 index 0000000..d1bb8af --- /dev/null +++ b/arch/m68k/swapcontext.S @@ -0,0 +1,39 @@ +/* + * Copyright (c) 2020 Ariadne Conill + * + * Permission to use, copy, modify, and/or distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * This software is provided 'as is' and without any warranty, express or + * implied. In no event shall the authors be liable for any damages arising + * from the use of this software. + */ + +#include "defs.h" + +ALIAS(swapcontext, __swapcontext) + +FUNC(__swapcontext) + move.l 4(%sp), %a0 /* load save ucontext_t pointer from stack */ + + movem.l %d2-%d7, REG_OFFSET(REG_D2)(%a0) /* preserve $d2 through $d7 */ + movem.l %a2-%a6, REG_OFFSET(REG_A2)(%a0) /* preserve $a2 through $a6 */ + + lea 4(%sp), %a1 /* load stack pointer into $a1 */ + move.l %a1, REG_OFFSET(REG_SP)(%a0) /* store $a1 in ucontext */ + move.l (%sp), REG_OFFSET(REG_PC)(%a0) /* store return address in ucontext's PC register */ + + move.l 8(%sp), %a0 /* load new ucontext_t pointer from stack */ + + move.l REG_OFFSET(REG_SP)(%a0), %sp /* load new stack pointer */ + + movem.l REG_OFFSET(REG_D2)(%a0), %d2-%d7 /* load $d2 through $d7 */ + movem.l REG_OFFSET(REG_A2)(%a0), %a2-%a6 /* load $a2 through $a6 */ + + clr.l %d0 /* clear $d0 */ + + move.l REG_OFFSET(REG_PC)(%a0), %a1 /* load jump target */ + + jmp (%a1) /* jump to *$a1 */ +END(__swapcontext)