Implement 2DROP, 2DUP, 2SWAP as asm primitives.

diff --git a/jonesforth.S b/jonesforth.S
index c7309fd..ad93261 100644 (file)
--- a/jonesforth.S
+++ b/jonesforth.S
@@ -1,11 +1,11 @@
 /*     A sometimes minimal FORTH compiler and tutorial for Linux / i386 systems. -*- asm -*-
        By Richard W.M. Jones <rich@annexia.org> http://annexia.org/forth
        This is PUBLIC DOMAIN (see public domain release statement below).
-       $Id: jonesforth.S,v 1.43 2007-10-10 13:01:05 rich Exp $
+       $Id: jonesforth.S,v 1.44 2007-10-11 07:38:31 rich Exp $
 
        gcc -m32 -nostdlib -static -Wl,-Ttext,0 -Wl,--build-id=none -o jonesforth jonesforth.S
 */
-       .set JONES_VERSION,43
+       .set JONES_VERSION,44
 /*
        INTRODUCTION ----------------------------------------------------------------------
 
@@ -730,6 +730,29 @@ code_\label :                      // assembler code follows
        push %ecx
        NEXT
 
+       defcode "2DROP",5,,TWODROP // drop top two elements of stack
+       pop %eax
+       pop %eax
+       NEXT
+
+       defcode "2DUP",4,,TWODUP // duplicate top two elements of stack
+       mov (%esp),%eax
+       mov 4(%esp),%ebx
+       push %ebx
+       push %eax
+       NEXT
+
+       defcode "2SWAP",5,,TWOSWAP // swap top two pairs of elements of stack
+       pop %eax
+       pop %ebx
+       pop %ecx
+       pop %edx
+       push %ebx
+       push %eax
+       push %edx
+       push %ecx
+       NEXT
+
        defcode "?DUP",4,,QDUP  // duplicate top of stack if non-zero
        movl (%esp),%eax
        test %eax,%eax