Fix stack allocation bug

Error in rounding stack allocator to nearest 16 divisible value

Pass all tests in chapter 9

Used as reference https://github.com/nlsandler/nqcc2

1 files changed, 6 insertions, 3 deletions

diff --git a/src/cljcc/compiler.clj b/src/cljcc/compiler.clj
index c1af6de..17da6cf 100644
--- a/src/cljcc/compiler.clj
+++ b/src/cljcc/compiler.clj
@@ -372,9 +372,12 @@
   Stack space allocated needs to be a multiple of 16. Rouding up the size of
   stack frame makes it easier to maintain stack alignment during function calls."
   [{instructions :instructions max-stack-val :max-stack-val}]
-  (let [stack-abs (abs max-stack-val)
-        stack-value (- (+ stack-abs (mod stack-abs 16)))]
-    (cons (allocate-stack-instruction stack-value) instructions)))
+  (let [v (abs max-stack-val)
+        v (cond
+              (= (mod v 16) 0) v
+              (< v 0) (- v (- 16 (mod v 16)))
+              :else (+ v (- 16 (mod v 16))))]
+    (cons (allocate-stack-instruction v) instructions)))
 
 (defn- parameters->assembly-instructions
   "Moves parameters from registers and stacks to pseudoregisters.