diff options
Diffstat (limited to 'contrib/syslinux-4.02/com32/gdbstub/int.S')
| -rw-r--r-- | contrib/syslinux-4.02/com32/gdbstub/int.S | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/contrib/syslinux-4.02/com32/gdbstub/int.S b/contrib/syslinux-4.02/com32/gdbstub/int.S new file mode 100644 index 0000000..2a1ff9d --- /dev/null +++ b/contrib/syslinux-4.02/com32/gdbstub/int.S @@ -0,0 +1,77 @@ + .section ".text","ax" + +#define SIGTRAP 5 + +#define SIZEOF_I386_REGS 32 +#define SIZEOF_I386_FLAGS 4 + +/* When invoked, the stack contains: eflags, cs, eip, signo. */ +#define IH_OFFSET_GDB_REGS ( 0 ) +#define IH_OFFSET_GDB_EIP ( IH_OFFSET_GDB_REGS + SIZEOF_I386_REGS ) +#define IH_OFFSET_GDB_EFLAGS ( IH_OFFSET_GDB_EIP + 4 ) +#define IH_OFFSET_GDB_SEG_REGS ( IH_OFFSET_GDB_EFLAGS + SIZEOF_I386_FLAGS ) +#define IH_OFFSET_GDB_END ( IH_OFFSET_GDB_SEG_REGS + 6 * 4 ) +#define IH_OFFSET_OLD_EIP ( IH_OFFSET_GDB_END ) +#define IH_OFFSET_OLD_CS ( IH_OFFSET_OLD_EIP + 4 ) +#define IH_OFFSET_OLD_EFLAGS ( IH_OFFSET_OLD_CS + 4 ) +#define IH_OFFSET_END ( IH_OFFSET_OLD_EFLAGS + 4 ) + +/* We also access the stack whilst still storing or restoring + * the register snapshot. Since ESP is in flux, we need + * special offsets. + */ +#define IH_OFFSET_FLUX_OLD_CS ( IH_OFFSET_OLD_CS - 44 ) +#define IH_OFFSET_FLUX_OLD_EFLAGS ( IH_OFFSET_OLD_EFLAGS - 40 ) +#define IH_OFFSET_FLUX_OLD_EIP ( IH_OFFSET_OLD_EIP - 36 ) +#define IH_OFFSET_FLUX_END ( IH_OFFSET_END - 20 ) + + .global int_handler +int_handler: + /* Store CPU state in GDB register snapshot */ + pushw $0 + pushw %gs + pushw $0 + pushw %fs + pushw $0 + pushw %es + pushw $0 + pushw %ds + pushw $0 + pushw %ss + pushw $0 + pushw IH_OFFSET_FLUX_OLD_CS + 2(%esp) + pushl IH_OFFSET_FLUX_OLD_EFLAGS(%esp) + pushl IH_OFFSET_FLUX_OLD_EIP(%esp) + pushl %edi + pushl %esi + pushl %ebp + leal IH_OFFSET_FLUX_END(%esp), %edi + pushl %edi /* old ESP */ + pushl %ebx + pushl %edx + pushl %ecx + pushl %eax + + /* Call GDB stub exception handler */ + movl $SIGTRAP, %eax + movl %esp, %edx + call gdbstub_handler + + /* Restore CPU state from GDB register snapshot */ + popl %eax + popl %ecx + popl %edx + popl %ebx + addl $4, %esp /* Changing ESP currently not supported */ + popl %ebp + popl %esi + popl %edi + popl IH_OFFSET_FLUX_OLD_EIP(%esp) + popl IH_OFFSET_FLUX_OLD_EFLAGS(%esp) + popl IH_OFFSET_FLUX_OLD_CS(%esp) + popl %ss + popl %ds + popl %es + popl %fs + popl %gs + iret |