| 0,0 → 1,60 |
|---|
| |
| .section .text |
| |
| #ifdef L_chkstk |
| .global ___chkstk |
| .global __alloca |
| |
| ___chkstk: |
| __alloca: |
| pushl %ecx /* save temp */ |
| leal 8(%esp), %ecx /* point past return addr */ |
| subl %eax, %ecx |
| cmpl %fs:8, %ecx # check low stack limit |
| jb 1f |
| |
| 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 |
| 1: |
| int3 #trap to debugger |
| .ascii "Stack overflow" |
| #endif |
| |
| #ifdef L_chkstk_ms |
| .global ___chkstk_ms |
| |
| ___chkstk_ms: |
| pushl %ecx /* save temp */ |
| pushl %eax |
| cmpl $0x1000, %eax /* > 4k ?*/ |
| leal 12(%esp), %ecx /* point past return addr */ |
| jb 2f |
| 1: |
| subl $0x1000, %ecx /* yes, move pointer down 4k*/ |
| cmpl %fs:8, %ecx /* check low stack limit */ |
| jb 3f |
| |
| orl $0x0, (%ecx) /* probe there */ |
| subl $0x1000, %eax /* decrement count */ |
| cmpl $0x1000, %eax |
| ja 1b /* and do it again */ |
| |
| 2: |
| subl %eax, %ecx |
| orl $0x0, (%ecx) /* less than 4k, just peek here */ |
| |
| popl %eax |
| popl %ecx |
| ret |
| 3: |
| int3 #trap to debugger |
| .ascii "Stack overflow" |
| #endif |