Extend .advance to allow a filler expression.

src/Ophis/CorePragmas.py

@@ -94,8 +94,13 @@ def pragmaOrg(ppt, line, result):
 def pragmaAdvance(ppt, line, result):
     "Outputs filler until reaching the target PC"
     newPC = FE.parse_expr(line)
+    if str(line.lookahead(0)) == ",":
+        line.pop()
+        fillexpr = FE.parse_expr(line)
+    else:
+        fillexpr = IR.ConstantExpr(0)
     line.expect("EOL")
-    result.append(IR.Node(ppt, "Advance", newPC))
+    result.append(IR.Node(ppt, "Advance", newPC, fillexpr))
 
 def pragmaCheckpc(ppt, line, result):
     "Enforces that the PC has not exceeded a certain point"

src/Ophis/Passes.py

@@ -575,7 +575,6 @@ class Assembler(Pass):
         if (pc > target):
             Err.log("Attempted to .advance backwards: $%x to $%x" % (pc, target))
         else:
-            zero = IR.ConstantExpr(0)
-            for i in xrange(target-pc): self.outputbyte(zero, env)
+            for i in xrange(target-pc): self.outputbyte(node.data[1], env)
             self.filler += target-pc
         env.setPC(target)

tests/testdata.oph

@@ -1,7 +1,9 @@
-; This data file just dumps out $00-$0F repeatedly with different forms.
-
+; This data file just dumps out $00-$0F repeatedly with different forms,
+; bracketed by $00s and then $60s.
+.advance $10, ^
 .byte 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
 .word 256, $0302, $0504, $0706, $0908, $0b0a, $0d0c, $0f0e
 .dword $03020100, $07060504, $0b0a0908, $0f0e0d0c
 .wordbe 1, $0203, $0405, $0607, $0809, $0a0b, $0c0d, $0e0f
 .dwordbe $010203, $04050607, $08090a0b, $0c0d0e0f
+.advance $70, ^