Adding U<.

common/base_tests.fs

@@ -217,3 +217,12 @@ e: test-/cell
   -10 cells cell/ -10 =assert
   -10 cells 1- cell/ -11 =assert
 ;e
+
+e: test-u<
+  1 3 u< assert
+  3 1 u< 0= assert
+  0 -1 u< assert
+  -1 0 u< 0= assert
+  0 0 u< 0= assert
+  -1 -1 u< 0= assert
+;e

common/forth_namespace_tests.fs

@@ -227,6 +227,7 @@ e: check-tier0-opcodes
   out: literal 
   out: 0= 
   out: 0< 
+  out: U< 
   out: + 
   out: U/MOD 
   out: */MOD 

common/tier0_opcodes.h

@@ -106,6 +106,7 @@ typedef struct {
   YV(internals, NOP, ) \
   X("0=", ZEQUAL, tos = !tos ? -1 : 0) \
   X("0<", ZLESS, tos = (tos|0) < 0 ? -1 : 0) \
+  X("U<", ULESS, tos = ((ucell_t) *sp) < ((ucell_t) tos) ? -1 : 0; --sp) \
   X("+", PLUS, tos += *sp--) \
   X("U/MOD", USMOD, w = *sp; *sp = (ucell_t) w % (ucell_t) tos; \
                     tos = (ucell_t) w / (ucell_t) tos) \