From b664db740604014c5c7748de8efceddb33baa06e Mon Sep 17 00:00:00 2001
From: Rob McMullen <feedback@playermissile.com>
Date: Thu, 17 May 2018 09:51:33 -0700
Subject: [PATCH] Changed header to define external vars to prevent multiple
 symbol definitions if included in multiple C files * space is reserved for
 the variables in 6502.c

---
 6502.c | 10 ++++++++++
 6502.h | 20 ++++++++++----------
 2 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/6502.c b/6502.c
index c31c17b..2323a83 100644
--- a/6502.c
+++ b/6502.c
@@ -4,6 +4,16 @@
 
 #include "6502.h"
 
+uint8_t memory[1<<16];
+uint8_t A;
+uint8_t X;
+uint8_t Y;
+uint16_t PC;
+uint8_t SP;
+uint8_t extra_cycles;
+uint64_t total_cycles;
+union StatusReg SR;
+
 int lengths[NUM_MODES]; // instruction length table, indexed by addressing mode
 uint8_t * (*get_ptr[NUM_MODES])(); // addressing mode decoder table
 Instruction instructions[0x100]; // instruction data table
diff --git a/6502.h b/6502.h
index e865a36..7565900 100644
--- a/6502.h
+++ b/6502.h
@@ -10,14 +10,14 @@
 #define RST_VEC 0xFFFC
 #define IRQ_VEC 0xFFFE
 
-uint8_t memory[1<<16];
-uint8_t A;
-uint8_t X;
-uint8_t Y;
-uint16_t PC;
-uint8_t SP; // points to first empty stack location
-uint8_t extra_cycles;
-uint64_t total_cycles;
+extern uint8_t memory[1<<16];
+extern uint8_t A;
+extern uint8_t X;
+extern uint8_t Y;
+extern uint16_t PC;
+extern uint8_t SP; // points to first empty stack location
+extern uint8_t extra_cycles;
+extern uint64_t total_cycles;
 
 void * read_addr;
 void * write_addr;
@@ -38,7 +38,7 @@ union StatusReg { // this means we can access the status register as a byte, or
 	uint8_t byte;
 };
 
-union StatusReg SR;
+extern union StatusReg SR;
 
 typedef enum {
 	ACC,
@@ -64,7 +64,7 @@ typedef struct {
 	uint8_t cycles;
 } Instruction;
 
-Instruction instructions[0x100];
+extern Instruction instructions[0x100];
 
 void init_tables();