rt: Fix assembler for C calls to work more like a regular function call

This commit is contained in:
Patrick Walton 2011-09-29 17:32:28 -07:00
parent 6dece91ed3
commit e31849fb79

View File

@ -1,14 +1,17 @@
.text
// upcall_call_c_stack(void (*fn)(), void *new_esp)
//
// Note that we could use |enter| and |leave| but the manuals tell me they're
// slower.
.globl _upcall_call_c_stack
_upcall_call_c_stack:
movl %esp,%ecx // grab esp
movl 8(%esp),%eax // save fn
pushl %ebp
movl %esp,%ebp // save esp
movl 8(%esp),%eax // eax = callee
movl 12(%esp),%esp // switch stack
pushl %ecx // save esp on stack
calll *%eax
popl %esp // restore esp
movl %ebp,%esp // would like to use "leave" but it's slower
popl %ebp
ret