From dad97a25a538a53d27b037e0d7ad03d93a5fbff0 Mon Sep 17 00:00:00 2001
From: Nathan Braswell <miloignis@gmail.com>
Date: Tue, 27 Feb 2018 21:27:29 -0500
Subject: [PATCH] If statements work with the addition of jmp and jnz

---
 stdlib/bytecode_generator.krak | 49 +++++++++++++++++++++++++++++++---
 stdlib/type.krak               |  6 +++++
 2 files changed, 51 insertions(+), 4 deletions(-)

diff --git a/stdlib/bytecode_generator.krak b/stdlib/bytecode_generator.krak
index 7317437..79eb356 100644
--- a/stdlib/bytecode_generator.krak
+++ b/stdlib/bytecode_generator.krak
@@ -78,6 +78,8 @@ adt byte_inst {
     add: add,
     ldr: ldr,
     str: str,
+    jmp: jmp,
+    jnz: jnz,
     call,
     ret
 }
@@ -100,6 +102,13 @@ obj str {
     var offset: int
     var from_reg: int
 }
+obj jmp {
+    var offset: int
+}
+obj jnz {
+    var reg: int
+    var offset: int
+}
 
 fun to_string(b: byte_inst): string {
     match (b) {
@@ -108,6 +117,8 @@ fun to_string(b: byte_inst): string {
         byte_inst::add(a)    return string("r") + a.to_reg + " = r" + a.a + " + r" + a.b
         byte_inst::ldr(l)    return string("r") + l.to_reg + " = ldr r" + l.from_reg + " (" + l.offset + ")"
         byte_inst::str(s)    return string("str(r") + s.to_reg + "(" + s.offset + ") <= r" + s.from_reg + ")"
+        byte_inst::jmp(j)    return string("jmp(pc += ") + j.offset + ")"
+        byte_inst::jnz(j)    return string("jmp(r") + j.reg + " != 0, pc += " + j.offset + ")"
         byte_inst::call()    return string("call")
         byte_inst::ret()     return string("ret")
     }
@@ -164,8 +175,9 @@ obj bytecode_function (Object) {
             res += "\t\t" + n->identifier.name + ": r0 + " + o
         })
         res += "\n\t bytecode\n"
+        var pc = 0
         instructions.for_each(fun(b: byte_inst) {
-            res += "\t\t" + to_string(b) + "\n"
+            res += string("\t\t") + pc++ + string(": ") + to_string(b) + "\n"
         })
         return res
     }
@@ -277,10 +289,19 @@ obj bytecode_generator (Object) {
         return -1
     }
     fun generate_if_statement(node: *ast_node): int {
-        generate(node->if_statement.condition)
+        var cond_reg = generate(node->if_statement.condition)
+        var jnz_index = functions.last().instructions.size
+        emit_jnz(cond_reg,0)
         generate(node->if_statement.then_part)
-        if (node->if_statement.else_part)
+        if (node->if_statement.else_part) {
+            var jmp_index = functions.last().instructions.size
+            emit_jmp(0)
+            functions.last().instructions[jnz_index].jnz.offset = functions.last().instructions.size - jnz_index
             generate(node->if_statement.else_part)
+            functions.last().instructions[jmp_index].jmp.offset = functions.last().instructions.size - jmp_index
+        } else {
+            functions.last().instructions[jnz_index].jnz.offset = functions.last().instructions.size - jnz_index
+        }
         return -1
     }
     fun generate_while_loop(node: *ast_node): int {
@@ -325,7 +346,10 @@ obj bytecode_generator (Object) {
         return generate(node->cast.value)
     }
     fun generate_value(node: *ast_node): int {
-        return emit_imm(string_to_num<int>(node->value.string_value))
+        if (node->value.value_type->is_bool())
+            return emit_imm((node->value.string_value == "true") cast int)
+        else
+            return emit_imm(string_to_num<int>(node->value.string_value))
     }
     fun generate_code_block(node: *ast_node): int {
         node->code_block.children.for_each(fun(child: *ast_node) {
@@ -410,6 +434,19 @@ obj bytecode_generator (Object) {
         functions.last().instructions.add(byte_inst::str(s))
         return -1
     }
+    fun emit_jmp(offset: int): int {
+        var j: jmp
+        j.offset = offset
+        functions.last().instructions.add(byte_inst::jmp(j))
+        return -1
+    }
+    fun emit_jnz(reg: int, offset: int): int {
+        var j: jnz
+        j.reg = reg
+        j.offset = offset
+        functions.last().instructions.add(byte_inst::jnz(j))
+        return -1
+    }
     fun emit_ret(): int {
         functions.last().instructions.add(byte_inst::ret())
         return -1
@@ -429,12 +466,16 @@ obj bytecode_generator (Object) {
         stack_mem.size = 10
         stack_mem.for_each(fun(i: ref int) { i = 0; })
         for (var i = 0; i < main_entry.instructions.size; i++;) {
+            println(string("evaling: ") + i + ": " + to_string(main_entry.instructions[i]))
             match(main_entry.instructions[i]) {
                 byte_inst::nop()     {}
                 byte_inst::imm(i)    registers[i.reg] = i.val
                 byte_inst::add(a)    registers[a.to_reg] = registers[a.a] + registers[a.b]
                 byte_inst::ldr(l)    registers[l.to_reg] = stack_mem[registers[l.from_reg] + l.offset]
                 byte_inst::str(s)    stack_mem[registers[s.to_reg] + s.offset] = registers[s.from_reg]
+                byte_inst::jmp(j)    i += j.offset - 1 // to counteract pc inc
+                byte_inst::jnz(j)    if (registers[j.reg] != 0)
+                                        i += j.offset - 1 // to counteract pc inc
                 byte_inst::call()    error("call")
                 /*byte_inst::ret()     return stack_mem[registers[0]]*/
                 byte_inst::ret()     {
diff --git a/stdlib/type.krak b/stdlib/type.krak
index 729f2fe..f3d2ae9 100644
--- a/stdlib/type.krak
+++ b/stdlib/type.krak
@@ -231,6 +231,12 @@ obj type (Object) {
         }
         return false
     }
+    fun is_bool(): bool {
+        match (base) {
+            base_type::boolean() return true
+        }
+        return false
+    }
     fun is_function(): bool {
         match (base) {
             base_type::function() return true