Make memory sizes parameters

asm/assemble.go

@@ -13,7 +13,10 @@ func Assemble(src []byte) (*vm.Program, error) {
 		return nil, err
 	}
 
-	ret := &vm.Program{}
+	ret := &vm.Program{
+		GlobalMemorySize:   parsed.GlobalMemorySize,
+		FunctionMemorySize: parsed.FunctionMemorySize,
+	}
 
 	for f, fnc := range parsed.Functions {
 		instrs, err := assembleFunction(fnc)

asm/disassemble.go

@@ -21,7 +21,14 @@ func Disassemble(prog *vm.Program) (string, error) {
 		fncs = append(fncs, dis)
 	}
 
-	return fmt.Sprintf("functions:\n%s", strings.Join(fncs, "")), nil
+	return fmt.Sprintf(`global_memory_size: %d
+function_memory_size: %d
+functions:
+%s`,
+		prog.GlobalMemorySize,
+		prog.FunctionMemorySize,
+		strings.Join(fncs, ""),
+	), nil
 }
 
 func disassembleFunction(fnc *vm.Function) (string, error) {

asm/parse.go

@@ -1,9 +1,13 @@
 package asm
 
+import "fmt"
+
 import "gopkg.in/yaml.v2"
 
 type program struct {
-	Functions []function `yaml:"functions"`
+	GlobalMemorySize   uint64     `yaml:"global_memory_size"`
+	FunctionMemorySize uint64     `yaml:"function_memory_size"`
+	Functions          []function `yaml:"functions"`
 }
 
 type function []instruction
@@ -18,5 +22,13 @@ func parse(src []byte) (*program, error) {
 		return nil, err
 	}
 
+	if prog.GlobalMemorySize == 0 {
+		return nil, fmt.Errorf("global_memory_size must be set and non-zero")
+	}
+
+	if prog.FunctionMemorySize == 0 {
+		return nil, fmt.Errorf("function_memory_size must be set and non-zero")
+	}
+
 	return prog, nil
 }