vendor/psm/src/arch/x86_64_windows_gnu.s

   1 #include "psm.h"
   2
   3 .text
   4
   5 .def rust_psm_stack_direction
   6 .scl 2
   7 .type 32
   8 .endef
   9 .globl rust_psm_stack_direction
  10 .p2align 4
  11 rust_psm_stack_direction:
  12 /* extern "sysv64" fn() -> u8 (%al) */
  13 .cfi_startproc
  14     movb $STACK_DIRECTION_DESCENDING, %al # always descending on x86_64
  15     retq
  16 .cfi_endproc
  17
  18 .def rust_psm_stack_pointer
  19 .scl 2
  20 .type 32
  21 .endef
  22 .globl rust_psm_stack_pointer
  23 .p2align 4
  24 rust_psm_stack_pointer:
  25 /* extern "sysv64" fn() -> *mut u8 (%rax) */
  26 .cfi_startproc
  27     leaq 8(%rsp), %rax
  28     retq
  29 .cfi_endproc
  30
  31
  32 .def rust_psm_replace_stack
  33 .scl 2
  34 .type 32
  35 .endef
  36 .globl rust_psm_replace_stack
  37 .p2align 4
  38 rust_psm_replace_stack:
  39 /* extern "sysv64" fn(%rdi: usize, %rsi: extern "sysv64" fn(usize), %rdx: *mut u8, %rcx: *mut u8) */
  40 .cfi_startproc
  41 /*
  42     All we gotta do is set the stack pointer to %rdx & tail-call the callback in %rsi.
  43
  44     8-byte offset necessary to account for the "return" pointer that would otherwise be placed onto
  45     stack with a regular call
  46 */
  47     movq %gs:0x08, %rdx
  48     movq %gs:0x10, %rcx
  49     leaq -8(%rdx), %rsp
  50     jmpq *%rsi
  51 .cfi_endproc
  52
  53
  54 .def rust_psm_on_stack
  55 .scl 2
  56 .type 32
  57 .endef
  58 .globl rust_psm_on_stack
  59 .p2align 4
  60 rust_psm_on_stack:
  61 /*
  62 extern "sysv64" fn(%rdi: usize, %rsi: usize,
  63                    %rdx: extern "sysv64" fn(usize, usize), %rcx: *mut u8, %r8: *mut u8)
  64
  65 NB: on Windows for SEH to work at all, the pointers in TIB, thread information block, need to be
  66 fixed up. Otherwise, it seems that exception mechanism on Windows will not bother looking for
  67 exception handlers at *all* if they happen to fall outside the are specified in TIB.
  68
  69 This necessitates an API difference from the usual 4-argument signature used elsewhere.
  70
  71 FIXME: this needs a catch-all exception handler that aborts in case somebody unwinds into here.
  72 */
  73 .cfi_startproc
  74     pushq %rbp
  75     .cfi_def_cfa %rsp, 16
  76     .cfi_offset %rbp, -16
  77     pushq %gs:0x08
  78     .cfi_def_cfa %rsp, 24
  79     pushq %gs:0x10
  80     .cfi_def_cfa %rsp, 32
  81
  82     movq  %rsp, %rbp
  83     .cfi_def_cfa_register %rbp
  84     movq %rcx, %gs:0x08
  85     movq %r8, %gs:0x10
  86     movq  %rcx, %rsp
  87     callq *%rdx
  88     movq  %rbp, %rsp
  89
  90     popq %gs:0x10
  91     .cfi_def_cfa %rsp, 24
  92     popq %gs:0x08
  93     .cfi_def_cfa %rsp, 16
  94     popq  %rbp
  95     .cfi_def_cfa %rsp, 8
  96     retq
  97 .cfi_endproc