-/* stuff needed for libgcc on win32. */
+/* stuff needed for libgcc on win32.
+ *
+ * Copyright (C) 1996, 1998, 2001, 2003, 2008, 2009 Free Software Foundation, Inc.
+ * Written By Steve Chamberlain
+ *
+ * This file 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.
+ *
+ * This file 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/>.
+ */
#ifdef L_chkstk
+/* Function prologue calls _alloca to probe the stack when allocating more
+ than CHECK_STACK_LIMIT bytes in one go. Touching the stack at 4K
+ increments is necessary to ensure that the guard pages used
+ by the OS virtual memory manger are allocated in correct sequence. */
+
.global ___chkstk
.global __alloca
+#ifndef _WIN64
___chkstk:
__alloca:
- pushl %ecx /* save temp */
- movl %esp,%ecx /* get sp */
- addl $0x8,%ecx /* and point to return addr */
+ pushl %ecx /* save temp */
+ leal 8(%esp), %ecx /* point past return addr */
+ cmpl $0x1000, %eax /* > 4k ?*/
+ jb Ldone
+
+Lprobe:
+ subl $0x1000, %ecx /* yes, move pointer down 4k*/
+ orl $0x0, (%ecx) /* probe there */
+ subl $0x1000, %eax /* decrement count */
+ cmpl $0x1000, %eax
+ ja Lprobe /* and do it again */
+
+Ldone:
+ subl %eax, %ecx
+ orl $0x0, (%ecx) /* less than 4k, just peek here */
+
+ movl %esp, %eax /* save old stack pointer */
+ movl %ecx, %esp /* decrement stack */
+ movl (%eax), %ecx /* recover saved temp */
+ movl 4(%eax), %eax /* recover return address */
+
+ /* Push the return value back. Doing this instead of just
+ jumping to %eax preserves the cached call-return stack
+ used by most modern processors. */
+ pushl %eax
+ ret
+#else
+/* __alloca is a normal function call, which uses %rcx as the argument. And stack space
+ for the argument is saved. */
+__alloca:
+ movq %rcx, %rax
+ addq $0x7, %rax
+ andq $0xfffffffffffffff8, %rax
+ popq %rcx /* pop return address */
+ popq %r10 /* Pop the reserved stack space. */
+ movq %rsp, %r10 /* get sp */
+ cmpq $0x1000, %rax /* > 4k ?*/
+ jb Ldone_alloca
-probe: cmpl $0x1000,%eax /* > 4k ?*/
- jb done
+Lprobe_alloca:
+ subq $0x1000, %r10 /* yes, move pointer down 4k*/
+ orq $0x0, (%r10) /* probe there */
+ subq $0x1000, %rax /* decrement count */
+ cmpq $0x1000, %rax
+ ja Lprobe_alloca /* and do it again */
- subl $0x1000,%ecx /* yes, move pointer down 4k*/
- orl $0x0,(%ecx) /* probe there */
- subl $0x1000,%eax /* decrement count */
- jmp probe /* and do it again */
+Ldone_alloca:
+ subq %rax, %r10
+ orq $0x0, (%r10) /* less than 4k, just peek here */
+ movq %r10, %rax
+ subq $0x8, %r10 /* Reserve argument stack space. */
+ movq %r10, %rsp /* decrement stack */
-done: subl %eax,%ecx
- orl $0x0,(%ecx) /* less that 4k, just peek here */
+ /* Push the return value back. Doing this instead of just
+ jumping to %rcx preserves the cached call-return stack
+ used by most modern processors. */
+ pushq %rcx
+ ret
- movl %esp,%eax
- movl %ecx,%esp /* decrement stack */
+/* ___chkstk is a *special* function call, which uses %rax as the argument.
+ We avoid clobbering the 4 integer argument registers, %rcx, %rdx,
+ %r8 and %r9, which leaves us with %rax, %r10, and %r11 to use. */
+___chkstk:
+ addq $0x7, %rax /* Make sure stack is on alignment of 8. */
+ andq $0xfffffffffffffff8, %rax
+ popq %r11 /* pop return address */
+ movq %rsp, %r10 /* get sp */
+ cmpq $0x1000, %rax /* > 4k ?*/
+ jb Ldone
- movl (%eax),%ecx /* recover saved temp */
- movl 4(%eax),%eax /* get return address */
- jmp *%eax
+Lprobe:
+ subq $0x1000, %r10 /* yes, move pointer down 4k*/
+ orl $0x0, (%r10) /* probe there */
+ subq $0x1000, %rax /* decrement count */
+ cmpq $0x1000, %rax
+ ja Lprobe /* and do it again */
+Ldone:
+ subq %rax, %r10
+ orl $0x0, (%r10) /* less than 4k, just peek here */
+ movq %r10, %rsp /* decrement stack */
+ /* Push the return value back. Doing this instead of just
+ jumping to %r11 preserves the cached call-return stack
+ used by most modern processors. */
+ pushq %r11
+ ret
+#endif
#endif
projects / msp430-gcc.git / blobdiff