From c80637cf6c62e9ad1b1de78ae14907391946781f Mon Sep 17 00:00:00 2001
From: Natapat Samutpong <natapat.samutpong@gmail.com>
Date: Thu, 27 Jan 2022 09:12:49 +0700
Subject: [PATCH] feat: simplify if compilation

---
 blspc/src/compiler/compile.rs |  9 +++------
 blspc/src/vm/instr.rs         | 13 ++-----------
 2 files changed, 5 insertions(+), 17 deletions(-)

diff --git a/blspc/src/compiler/compile.rs b/blspc/src/compiler/compile.rs
index ae6c09c..373bb2c 100644
--- a/blspc/src/compiler/compile.rs
+++ b/blspc/src/compiler/compile.rs
@@ -50,12 +50,9 @@ impl Compiler {
                             "if" => {
                                 // TODO: Remove .clone()
                                 let mut cond = self.compile(cdr[0].clone(), depth + 1)?;
-                                let cond_register = self.current_register();
-
                                 result.append(&mut cond);
 
-                                result.push(Instr::JumpIfFalse {
-                                    cond: cond_register,
+                                result.push(Instr::PopJumpIfFalse {
                                     to: 999, // To be replaced later
                                     label: self.next_label(),
                                 });
@@ -68,8 +65,8 @@ impl Compiler {
 
                                 let idx = result.len() - 1;
                                 match result[idx] {
-                                    Instr::JumpIfFalse { cond: c, to: _, label: l } => {
-                                        result[idx] = Instr::JumpIfFalse { cond: c, to: else_label, label: l, };
+                                    Instr::PopJumpIfFalse { to: _, label: l } => {
+                                        result[idx] = Instr::PopJumpIfFalse { to: else_label, label: l, };
                                     }
                                     _ => unreachable!(),
                                 }
diff --git a/blspc/src/vm/instr.rs b/blspc/src/vm/instr.rs
index 625df5f..ac95168 100644
--- a/blspc/src/vm/instr.rs
+++ b/blspc/src/vm/instr.rs
@@ -81,14 +81,9 @@ pub enum Instr {
     // Stack arithmetic.
     Add { label: usize }, Sub { label: usize },
     Mul { label: usize }, Div { label: usize },
-    // Immediate arithmetic.
-    IAdd { lhs: Register, rhs: Register, to: Register, label: usize },
-    ISub { lhs: Register, rhs: Register, to: Register, label: usize },
-    IMul { lhs: Register, rhs: Register, to: Register, label: usize },
-    IDiv { lhs: Register, rhs: Register, to: Register, label: usize },
     // Jumping
     Jump { to: usize, label: usize },
-    JumpIfFalse { cond: Register, to: usize, label: usize },
+    PopJumpIfFalse { to: usize, label: usize },
 
     Return { value: Register, label: usize },
 }
@@ -105,12 +100,8 @@ impl Display for Instr {
             Instr::Sub { label }                   => write!(f, "{}: SUB", label),
             Instr::Mul { label }                   => write!(f, "{}: MUL", label),
             Instr::Div { label }                   => write!(f, "{}: DIV", label),
-            Instr::IAdd { lhs, rhs, to, label }    => write!(f, "{}: IADD {} {} {}", label, lhs, rhs, to),
-            Instr::ISub { lhs, rhs, to, label }    => write!(f, "{}: ISUB {} {} {}", label, lhs, rhs, to),
-            Instr::IMul { lhs, rhs, to, label }    => write!(f, "{}: IMUL {} {} {}", label, lhs, rhs, to),
-            Instr::IDiv { lhs, rhs, to, label }    => write!(f, "{}: IDIV {} {} {}", label, lhs, rhs, to),
             Instr::Jump { to, label }              => write!(f, "{}: JUMP {}", label, to),
-            Instr::JumpIfFalse { cond, to, label } => write!(f, "{}: JUMP_IF_FALSE {} {}", label, cond, to),
+            Instr::PopJumpIfFalse { to, label }    => write!(f, "{}: POP_JUMP_IF_FALSE {}", label, to),
             Instr::Return { value, label }         => write!(f, "{}: RETURN {}", label, value),
         }
     }