Fixed register allocation on function calls

src/core/CallSafe.go

@@ -0,0 +1,33 @@
+package core
+
+import (
+	"slices"
+
+	"git.akyoto.dev/cli/q/src/asm"
+	"git.akyoto.dev/cli/q/src/cpu"
+)
+
+// CallSafe pushes used registers to the stack, executes the call and restores the original register value.
+func (f *Function) CallSafe(fn *Function, registers []cpu.Register) {
+	for _, register := range f.CPU.Output {
+		f.SaveRegister(register)
+	}
+
+	for _, register := range f.CPU.General {
+		if f.RegisterIsUsed(register) {
+			f.Register(asm.PUSH, register)
+		}
+	}
+
+	f.Call(fn.UniqueName)
+
+	for _, register := range slices.Backward(f.CPU.General) {
+		if f.RegisterIsUsed(register) {
+			f.Register(asm.POP, register)
+		}
+	}
+
+	for _, register := range registers {
+		f.FreeRegister(register)
+	}
+}