init

1 files changed, 32 insertions, 0 deletions

diff --git a/vm/stack.go b/vm/stack.go
new file mode 100644
index 0000000..fc1cbd4
--- /dev/null
+++ b/vm/stack.go
@@ -0,0 +1,32 @@
+package main
+
+import (
+	"log"
+
+	 "github.com/holiman/uint256"
+)
+
+const STACK_CAP = (1 << 10)
+
+type Stack []uint256.Int
+
+func (s *Stack) Push(x *uint256.Int) {
+	*s = append(*s, *x)
+	if len(*s) + 1 > STACK_CAP {
+		log.Fatal("stack overflow")
+	}
+}
+
+func (s *Stack) Pop() *uint256.Int {
+	if len(*s) <= 0 {
+		log.Fatal("stack underflow")
+	}
+
+	r := (*s)[len(*s)-1]
+	*s = (*s)[:len(*s)-1]
+	return &r
+}
+
+func (s *Stack) Peek() *uint256.Int {
+	return &(*s)[len(*s)-1]	
+}