Import Dev86-0.0.4.tar.gzv0.0.4

1 files changed, 50 insertions, 0 deletions

diff --git a/libc-0.0.4/bcc/alloca.c b/libc-0.0.4/bcc/alloca.c
new file mode 100644
index 0000000..4f85047
--- /dev/null
+++ b/libc-0.0.4/bcc/alloca.c
@@ -0,0 +1,50 @@
+/* Copyright (C) 1995,1996 Robert de Bath <rdebath@cix.compulink.co.uk>
+ * This file is part of the Linux-8086 C library and is distributed
+ * under the GNU Library General Public License.
+ */
+
+/* Alloca is a nice interesting function */
+/* Needs change to BCC to work, as BCC doesn't use 'mov sp,bp:pop bp' */
+/* The only other way to do it is to use malloc and the emacs alloca */
+
+#if 0
+THIS IS BROKEN!!!
+
+#asm
+export _alloca
+  .text
+_alloca:
+  pop	cx	! The program counter
+  pop	ax	! The argument (>1 arg == snafu)
+  inc	ax
+  and	al,$FE	! Round up to even
+
+  test	ax,ax
+  jz	too_big	! Well _I_ think it means 64k ! :-)     (ANSI too IIUC)
+
+  mov	bx,sp
+  sub	bx,ax	! Calc new SP
+  jb	too_big	! SP wrapped, snafu!
+
+  mov	ax,[brk_addr]
+  add	ax,#64	! Check if brk has allocated the memory first but
+  cmp	bx,ax	! leave a little bit of space before we collide!
+  jb	too_big
+
+  xchg	bx,sp	! Put it in place, may need the old SP for other args
+  mov	ax,sp	! The bottom of the area allocated
+
+		! This is needed if si/di popped before mov sp,bp
+  !push	[bx+4]	! This copies the saved register vars and possibly a temp
+  !push	[bx+2]	! value, beware snafu if called within complex expression!
+  !push	[bx]	! 
+
+  push	ax	! Anything really, it will be deallocated by the caller
+  jmp	cx	! Return
+
+too_big:
+  xor	ax,ax	! Sorry not enough stack
+  push	ax	! More junk
+  jmp	cx	! Return
+#endasm
+#endif