Added

diff --git a/mach/i386/libdb/.distr b/mach/i386/libdb/.distr
new file mode 100644 (file)
index 0000000..af5eda4
--- /dev/null
+++ b/mach/i386/libdb/.distr
@@ -0,0 +1 @@
+machdep.s

diff --git a/mach/i386/libdb/machdep.s b/mach/i386/libdb/machdep.s
new file mode 100644 (file)
index 0000000..eba8b04
--- /dev/null
+++ b/mach/i386/libdb/machdep.s
@@ -0,0 +1,72 @@
+.define ___Get_PC, ___Set_PC, ___u_LiB
+.sect .text; .sect .rom; .sect .data
+
+! $Header$
+
+! This is the machine-dependant part of the ACK debugger support.
+! ___Get_PC takes a frame pointer (local base) argument and returns the
+!          return address from this frame.
+! ___Set_PC takes a frame pointer (local base) argument plus a return
+!          address and sets the return address of this frame to the
+!          return address supplied.
+! ___u_LiB  saves the scratch registers and then calls ___uX_LiB;
+!          when ___uX_LiB returns, the scratch registers are restored.
+!          ___u_LiB is the solution chosen for the Intel 80386 back-end.
+!          Other back-ends could choose different solutions.
+
+! The local base of ___uX_LiB is kind of special: because of ___u_LiB,
+! the "interesting" return address of this particular stack-frame is found
+! in a different place than the one of a normal stack-frame:
+! the "interesting" return address is in fact the return address of
+! ___u_LiB. Therefore, we save the local base of ___uX_LiB in sv_bp.
+
+.sect .data
+sv_bp:
+       .data4 0
+
+.sect .text
+___Get_PC:
+       mov     ebx,esp
+       mov     eax,4(ebx)
+       or      eax,eax
+       je      1f
+       cmp     (sv_bp),eax
+       je      2f
+       mov     eax,4(eax)
+1:
+       ret
+2:
+       mov     eax,28(eax)
+       ret
+
+___Set_PC:
+       mov     ebx,esp
+       mov     eax,4(ebx)
+       mov     ebx,8(ebx)
+       or      eax,eax
+       je      1f
+       cmp     (sv_bp),eax
+       je      2f
+       mov     4(eax),ebx
+1:
+       ret
+2:
+       mov     28(eax),ebx
+       ret
+
+___u_LiB:
+       push    eax
+       push    ebx
+       push    ecx
+       push    edx
+       push    (sv_bp)
+       mov     eax,esp
+       sub     eax,8
+       mov     (sv_bp),eax     ! this is the LB of __uX_LiB
+       call    ___uX_LiB
+       pop     (sv_bp)
+       pop     edx
+       pop     ecx
+       pop     ebx
+       pop     eax
+       ret