From 3f20646b1678740d4fee863434d12434640e260f Mon Sep 17 00:00:00 2001
From: Nathan Braswell <miloignis@gmail.com>
Date: Sat, 17 Mar 2018 12:47:01 -0400
Subject: [PATCH] Fixed pointer arithmatic

---
 stdlib/bytecode_generator.krak | 34 +++++++++++++++++++++++++---------
 1 file changed, 25 insertions(+), 9 deletions(-)

diff --git a/stdlib/bytecode_generator.krak b/stdlib/bytecode_generator.krak
index ef7e991..9c60cd1 100644
--- a/stdlib/bytecode_generator.krak
+++ b/stdlib/bytecode_generator.krak
@@ -590,30 +590,46 @@ obj bytecode_generator (Object) {
             }
 
             var params = parameter_nodes.map(fun(n: *ast_node): int return generate(n);)
+            var lhs_type = get_ast_type(parameter_nodes[0])
             if        (name == "+") {
-                if (params.size == 1)
+                if (params.size == 1) {
                     return emit_smul(params[0], emit_or(emit_gz(params[0]), emit_smul(emit_lz(params[0]), emit_imm(-1))))
-                else
-                    return emit_add(params[0], params[1])
+                } else {
+                    if (lhs_type->indirection == 0) {
+                        return emit_add(params[0], params[1])
+                    } else {
+                        return emit_add(params[0], emit_smul(params[1], emit_imm(type_size(lhs_type->clone_with_decreased_indirection()))))
+                    }
+                }
             } else if (name == "-") {
-                if (params.size == 1)
+                if (params.size == 1) {
                     return emit_addi(emit_not(params[0]), 1)
-                else
-                    return emit_add(params[0], emit_addi(emit_not(params[1]), 1))
+                } else {
+                    if (lhs_type->indirection == 0) {
+                        return emit_add(params[0], params[1])
+                    } else {
+                        return emit_add(params[0], emit_addi(emit_not(emit_smul(params[1], emit_imm(type_size(lhs_type->clone_with_decreased_indirection())))), 1))
+                    }
+                }
             } else if (name == "!") {
                 return emit_ez(params[0])
             } else if (name == "[]" || (name == "*" && params.size == 1)) {
+                var derefed_size = type_size(lhs_type->clone_with_decreased_indirection())
                 if (name == "[]") {
+                    var offset_reg = params[1]
+                    if (derefed_size != 1)
+                        offset_reg = emit_smul(offset_reg, emit_imm(derefed_size))
+                    var addr_reg = emit_add(params[0], offset_reg)
                     if (lvalue)
-                        return emit_add(params[0], params[1])
+                        return addr_reg
                     else
-                        return emit_ldr(emit_add(params[0], params[1]), 0, size_to_operand_size(type_size(get_ast_type(parameter_nodes[0])->clone_with_decreased_indirection())))
+                        return emit_ldr(addr_reg, 0, size_to_operand_size(derefed_size))
                 }
                 if (name == "*")  {
                     if (lvalue)
                         return params[0]
                     else
-                        return emit_ldr(params[0], 0, size_to_operand_size(type_size(get_ast_type(parameter_nodes[0])->clone_with_decreased_indirection())))
+                        return emit_ldr(params[0], 0, size_to_operand_size(derefed_size))
                 }
             } else if (name == "==" || name == "<=" || name == ">=" || name == "!=" || name == "<" || name == ">") {
                 var diff = emit_add(params[0], emit_addi(emit_not(params[1]), 1))