From: ceriel <none@none>
Date: Fri, 8 Nov 1991 15:44:30 +0000 (+0000)
Subject: Added
X-Git-Tag: release-5-5~651
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=7d0a89d420af275a343e023e512b28549d820c47;p=ack.git

Added
---

diff --git a/mach/i386/libdb/.distr b/mach/i386/libdb/.distr
new file mode 100644
index 000000000..af5eda499
--- /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
index 000000000..eba8b04c8
--- /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