From ac1d825f139cc917252de4f2f1040ceeb013f5d6 Mon Sep 17 00:00:00 2001
From: Derick Alangi <alangiderick@gmail.com>
Date: Wed, 16 Jun 2021 16:54:02 +0100
Subject: [PATCH 1/2] Add support for bitwise NOT (~) operator to pocketlang

Like other bitwise operators like: &, ^, >>, << etc, add support
for the bitwise NOT (~) operator.
---
 src/pk_core.c        |  8 ++++++++
 src/pk_core.h        |  1 +
 src/pk_vm.c          | 12 +++++++++++-
 tests/lang/basics.pk |  3 +++
 4 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/src/pk_core.c b/src/pk_core.c
index ba150ed..a10f070 100644
--- a/src/pk_core.c
+++ b/src/pk_core.c
@@ -1217,6 +1217,14 @@ Var varBitRshift(PKVM* vm, Var v1, Var v2) {
   return VAR_NULL;
 }
 
+Var varBitNot(PKVM* vm, Var v) {
+  int64_t i;
+
+  if (isInteger(v, &i))
+    return VAR_NUM((double)(~i));
+  return VAR_NULL;
+}
+
 bool varGreater(Var v1, Var v2) {
   double d1, d2;
 
diff --git a/src/pk_core.h b/src/pk_core.h
index ff391ce..205ad37 100644
--- a/src/pk_core.h
+++ b/src/pk_core.h
@@ -41,6 +41,7 @@ Var varBitOr(PKVM* vm, Var v1, Var v2);       // Returns v1 | v2.
 Var varBitXor(PKVM* vm, Var v1, Var v2);      // Returns v1 ^ v2.
 Var varBitLshift(PKVM* vm, Var v1, Var v2);   // Returns v1 << v2.
 Var varBitRshift(PKVM* vm, Var v1, Var v2);   // Returns v1 >> v2.
+Var varBitNot(PKVM* vm, Var v);               // Returns ~v.
 
 bool varGreater(Var v1, Var v2); // Returns v1 > v2.
 bool varLesser(Var v1, Var v2);  // Returns v1 < v2.
diff --git a/src/pk_vm.c b/src/pk_vm.c
index e2896c8..b21e349 100644
--- a/src/pk_vm.c
+++ b/src/pk_vm.c
@@ -1220,7 +1220,17 @@ static PkResult runFiber(PKVM* vm, Fiber* fiber) {
     }
 
     OPCODE(BIT_NOT):
-      TODO;
+    {
+      // Don't pop yet, we need the reference for gc.
+      Var val = POP();
+
+      Var result = varBitNot(vm, val);
+      DROP(); // val
+      PUSH(result);
+
+      CHECK_ERROR();
+      DISPATCH();
+    }
 
     // Do not ever use PUSH(binaryOp(vm, POP(), POP()));
     // Function parameters are not evaluated in a defined order in C.
diff --git a/tests/lang/basics.pk b/tests/lang/basics.pk
index c197c4f..e92106a 100644
--- a/tests/lang/basics.pk
+++ b/tests/lang/basics.pk
@@ -73,6 +73,9 @@ assert(8 >> 1 == 0x4)
 assert(8 >> 2 == 0b10)
 assert(0xa >> 1 == 5)
 
+assert(~8 == -9)
+assert(~1 == -2)
+
 x = 42  ; assert((x&=51) == 34)
 x = 123 ; assert((x&=324) == 64)
 for i in 0..1000

From fbcf6fc1a15eab6a10f39554aebe42692859e40c Mon Sep 17 00:00:00 2001
From: Derick Alangi <alangiderick@gmail.com>
Date: Wed, 16 Jun 2021 20:54:07 +0100
Subject: [PATCH 2/2] use PEEK() so we don't loose reference

---
 src/pk_core.c        | 6 +++---
 src/pk_vm.c          | 2 +-
 tests/lang/basics.pk | 2 ++
 3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/pk_core.c b/src/pk_core.c
index a10f070..e963a48 100644
--- a/src/pk_core.c
+++ b/src/pk_core.c
@@ -1220,9 +1220,9 @@ Var varBitRshift(PKVM* vm, Var v1, Var v2) {
 Var varBitNot(PKVM* vm, Var v) {
   int64_t i;
 
-  if (isInteger(v, &i))
-    return VAR_NUM((double)(~i));
-  return VAR_NULL;
+  if (!validateInteger(vm, v, &i, "Unary operand")) return VAR_NULL;
+
+  return VAR_NUM((double)(~i));
 }
 
 bool varGreater(Var v1, Var v2) {
diff --git a/src/pk_vm.c b/src/pk_vm.c
index b21e349..1044440 100644
--- a/src/pk_vm.c
+++ b/src/pk_vm.c
@@ -1222,7 +1222,7 @@ static PkResult runFiber(PKVM* vm, Fiber* fiber) {
     OPCODE(BIT_NOT):
     {
       // Don't pop yet, we need the reference for gc.
-      Var val = POP();
+      Var val = PEEK(-1);
 
       Var result = varBitNot(vm, val);
       DROP(); // val
diff --git a/tests/lang/basics.pk b/tests/lang/basics.pk
index e92106a..f14b3c8 100644
--- a/tests/lang/basics.pk
+++ b/tests/lang/basics.pk
@@ -75,6 +75,8 @@ assert(0xa >> 1 == 5)
 
 assert(~8 == -9)
 assert(~1 == -2)
+assert(~0b0 == -1)
+assert(~0x1 == -2)
 
 x = 42  ; assert((x&=51) == 34)
 x = 123 ; assert((x&=324) == 64)