From b5d3c8725335d18c69e84c4a01adb7ef27a5d473 Mon Sep 17 00:00:00 2001
From: Calvin Rose <calsrose@gmail.com>
Date: Sun, 9 Jul 2023 21:28:08 -0500
Subject: [PATCH] Add new opcode subtract immediate.

---
 src/core/asm.c      | 1 +
 src/core/bytecode.c | 2 ++
 src/core/cfuns.c    | 2 +-
 src/core/vm.c       | 5 ++++-
 src/include/janet.h | 1 +
 5 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/core/asm.c b/src/core/asm.c
index e5712cc1..14fa28c0 100644
--- a/src/core/asm.c
+++ b/src/core/asm.c
@@ -138,6 +138,7 @@ static const JanetInstructionDef janet_ops[] = {
     {"sru", JOP_SHIFT_RIGHT_UNSIGNED},
     {"sruim", JOP_SHIFT_RIGHT_UNSIGNED_IMMEDIATE},
     {"sub", JOP_SUBTRACT},
+    {"subim", JOP_SUBTRACT_IMMEDIATE},
     {"tcall", JOP_TAILCALL},
     {"tchck", JOP_TYPECHECK}
 };
diff --git a/src/core/bytecode.c b/src/core/bytecode.c
index 821bf42d..e0b25cfd 100644
--- a/src/core/bytecode.c
+++ b/src/core/bytecode.c
@@ -37,6 +37,7 @@ enum JanetInstructionType janet_instructions[JOP_INSTRUCTION_COUNT] = {
     JINT_0, /* JOP_RETURN_NIL, */
     JINT_SSI, /* JOP_ADD_IMMEDIATE, */
     JINT_SSS, /* JOP_ADD, */
+    JINT_SSI, /* JOP_SUBTRACT_IMMEDIATE, */
     JINT_SSS, /* JOP_SUBTRACT, */
     JINT_SSI, /* JOP_MULTIPLY_IMMEDIATE, */
     JINT_SSS, /* JOP_MULTIPLY, */
@@ -251,6 +252,7 @@ void janet_bytecode_movopt(JanetFuncDef *def) {
                 case JOP_SIGNAL:
                 /* Write A, Read B */
                 case JOP_ADD_IMMEDIATE:
+                case JOP_SUBTRACT_IMMEDIATE:
                 case JOP_MULTIPLY_IMMEDIATE:
                 case JOP_DIVIDE_IMMEDIATE:
                 case JOP_SHIFT_LEFT_IMMEDIATE:
diff --git a/src/core/cfuns.c b/src/core/cfuns.c
index be61da80..13c86dec 100644
--- a/src/core/cfuns.c
+++ b/src/core/cfuns.c
@@ -260,7 +260,7 @@ static JanetSlot do_add(JanetFopts opts, JanetSlot *args) {
     return opreduce(opts, args, JOP_ADD, JOP_ADD_IMMEDIATE, janet_wrap_integer(0), janet_wrap_integer(0));
 }
 static JanetSlot do_sub(JanetFopts opts, JanetSlot *args) {
-    return opreduce(opts, args, JOP_SUBTRACT, -JOP_ADD_IMMEDIATE, janet_wrap_integer(0), janet_wrap_integer(0));
+    return opreduce(opts, args, JOP_SUBTRACT, JOP_SUBTRACT_IMMEDIATE, janet_wrap_integer(0), janet_wrap_integer(0));
 }
 static JanetSlot do_mul(JanetFopts opts, JanetSlot *args) {
     return opreduce(opts, args, JOP_MULTIPLY, JOP_MULTIPLY_IMMEDIATE, janet_wrap_integer(1), janet_wrap_integer(1));
diff --git a/src/core/vm.c b/src/core/vm.c
index 132d8c09..5e881772 100644
--- a/src/core/vm.c
+++ b/src/core/vm.c
@@ -347,6 +347,7 @@ static JanetSignal run_vm(JanetFiber *fiber, Janet in) {
         &&label_JOP_RETURN_NIL,
         &&label_JOP_ADD_IMMEDIATE,
         &&label_JOP_ADD,
+        &&label_JOP_SUBTRACT_IMMEDIATE,
         &&label_JOP_SUBTRACT,
         &&label_JOP_MULTIPLY_IMMEDIATE,
         &&label_JOP_MULTIPLY,
@@ -593,7 +594,6 @@ static JanetSignal run_vm(JanetFiber *fiber, Janet in) {
         &&label_unknown_op,
         &&label_unknown_op,
         &&label_unknown_op,
-        &&label_unknown_op,
         &&label_unknown_op
     };
 #endif
@@ -683,6 +683,9 @@ static JanetSignal run_vm(JanetFiber *fiber, Janet in) {
     VM_OP(JOP_ADD)
     vm_binop(+);
 
+    VM_OP(JOP_SUBTRACT_IMMEDIATE)
+    vm_binop_immediate(-);
+
     VM_OP(JOP_SUBTRACT)
     vm_binop(-);
 
diff --git a/src/include/janet.h b/src/include/janet.h
index ada92277..e59318f1 100644
--- a/src/include/janet.h
+++ b/src/include/janet.h
@@ -1262,6 +1262,7 @@ enum JanetOpCode {
     JOP_RETURN_NIL,
     JOP_ADD_IMMEDIATE,
     JOP_ADD,
+    JOP_SUBTRACT_IMMEDIATE,
     JOP_SUBTRACT,
     JOP_MULTIPLY_IMMEDIATE,
     JOP_MULTIPLY,