diff options
Diffstat (limited to 'gcc/config/i386/cygwin.asm')
| -rw-r--r-- | gcc/config/i386/cygwin.asm | 71 |
1 files changed, 55 insertions, 16 deletions
diff --git a/gcc/config/i386/cygwin.asm b/gcc/config/i386/cygwin.asm index 5b656892d5f..371feae8864 100644 --- a/gcc/config/i386/cygwin.asm +++ b/gcc/config/i386/cygwin.asm @@ -42,27 +42,66 @@ .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 -probe: cmpl $0x1000,%eax /* > 4k ?*/ - jb done +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 */ - 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: + subl %eax, %ecx + orl $0x0, (%ecx) /* less than 4k, just peek here */ -done: subl %eax,%ecx - orl $0x0,(%ecx) /* less that 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 */ - movl %esp,%eax - movl %ecx,%esp /* decrement stack */ + /* 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. */ +__alloca: + movq %rcx, %rax + /* FALLTHRU */ + +/* ___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: + 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 |