X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fruntime%2Fx86-64-assem.S;h=c4f543593fb90962f45082443d01800888c78c98;hb=d94c1b4a8c534bde146823f56558faf37cd4c4d7;hp=ac420108843e9d42c27b2502f69fdf129c64236e;hpb=9184392783512f76eb971b7e316c875e2a1eb94c;p=sbcl.git

diff --git a/src/runtime/x86-64-assem.S b/src/runtime/x86-64-assem.S
index ac42010..c4f5435 100644
--- a/src/runtime/x86-64-assem.S
+++ b/src/runtime/x86-64-assem.S
@@ -67,7 +67,7 @@
  * for this instruction in the SIGILL handler and if we see it, we
  * advance the EIP by two bytes to skip over ud2 instruction and
  * call sigtrap_handler. */
-#if defined(LISP_FEATURE_DARWIN)
+#if defined(LISP_FEATURE_UD2_BREAKPOINTS)
 #define TRAP ud2
 #else
 #define TRAP int3
@@ -194,7 +194,7 @@ Lstack:
 	xor	%rdx,%rdx	# clear any descriptor registers 
 	xor	%rdi,%rdi	# that we can't be sure we'll 
 	xor	%rsi,%rsi	# initialise properly.  XX do r8-r15 too?
-	shl	$3,%rcx		# (fixnumize num-args)
+	shl	$(N_FIXNUM_TAG_BITS),%rcx	# (fixnumize num-args)
 	cmp	$0,%rcx
 	je	Ldone
 	mov	0(%rbx),%rdx	# arg0
@@ -266,6 +266,7 @@ GNAME(fpu_restore):
 	.globl  GNAME(undefined_tramp)
 	TYPE(GNAME(undefined_tramp))
 GNAME(undefined_tramp):
+	pop	8(%rbp)         # Save return PC for backtrace.
 	TRAP
 	.byte	trap_Error
         .byte   2
@@ -343,6 +344,12 @@ GNAME(closure_tramp):
 /*
  * fun-end breakpoint magic
  */
+
+/*
+ * For an explanation of the magic involved in function-end
+ * breakpoints, see the implementation in ppc-assem.S.
+ */
+
 	.text
 	.globl 	GNAME(fun_end_breakpoint_guts)
 	.align	align_16byte