From ad90d9294ceb04793edbd6add4e2d4bd27eaeead Mon Sep 17 00:00:00 2001
From: Matthias Endler <matthias-endler@gmx.net>
Date: Fri, 29 Jan 2021 00:14:50 +0100
Subject: [PATCH] Statically initialize CPU

---
 no-std-example/Cargo.toml  |   5 ++
 no-std-example/src/main.rs | 124 +++++++++++++++++++------------------
 2 files changed, 68 insertions(+), 61 deletions(-)

diff --git a/no-std-example/Cargo.toml b/no-std-example/Cargo.toml
index 2c745bd..f6aba24 100644
--- a/no-std-example/Cargo.toml
+++ b/no-std-example/Cargo.toml
@@ -12,6 +12,11 @@ cortex-m-semihosting = "0.3.1"
 panic-halt = "0.2.0"
 mos6502 = { path = ".." }
 
+[dependencies.once_cell]
+version = "1.5.2"
+default-features = false
+features = []
+
 # Uncomment for the panic example.
 # panic-itm = "0.4.0"
 
diff --git a/no-std-example/src/main.rs b/no-std-example/src/main.rs
index 9d8ffe7..c553c08 100644
--- a/no-std-example/src/main.rs
+++ b/no-std-example/src/main.rs
@@ -10,73 +10,75 @@ use cortex_m_rt::entry;
 use mos6502::address::Address;
 use mos6502::cpu;
 
+use once_cell::unsync::Lazy;
+
 #[entry]
 fn main() -> ! {
-	loop {
-		let mut cpu = cpu::CPU::new();
+    let mut cpu = Lazy::new(|| cpu::CPU::new());
 
-		let zero_page_data = [
-			// ZeroPage data start
-			0x00, 0x02, // ADC ZeroPage target
-			0x00, 0x04, // ADC ZeroPageX target
-			0x00, 0x00, 0x00, 0x00, 0x10, // ADC IndexedIndirectX address
-			0x80, // ADC IndexedIndirectX address
-			0x00, 0x00, 0x00, 0x00, 0x00, 0x08, // ADC IndirectIndexedY address
-			0x80, // ADC IndirectIndexedY address
-		];
+    loop {
+        let zero_page_data = [
+            // ZeroPage data start
+            0x00, 0x02, // ADC ZeroPage target
+            0x00, 0x04, // ADC ZeroPageX target
+            0x00, 0x00, 0x00, 0x00, 0x10, // ADC IndexedIndirectX address
+            0x80, // ADC IndexedIndirectX address
+            0x00, 0x00, 0x00, 0x00, 0x00, 0x08, // ADC IndirectIndexedY address
+            0x80, // ADC IndirectIndexedY address
+        ];
 
-		let program = [
-			// Code start
-			0xA9, // LDA Immediate
-			0x01, //     Immediate operand
-			0x69, // ADC Immediate
-			0x07, //     Immediate operand
-			0x65, // ADC ZeroPage
-			0x01, //     ZeroPage operand
-			0xA2, // LDX Immediate
-			0x01, //     Immediate operand
-			0x75, // ADC ZeroPageX
-			0x02, //     ZeroPageX operand
-			0x6D, // ADC Absolute
-			0x01, //     Absolute operand
-			0x80, //     Absolute operand
-			0xA2, // LDX immediate
-			0x08, //     Immediate operand
-			0x7D, // ADC AbsoluteX
-			0x00, //     AbsoluteX operand
-			0x80, //     AbsoluteX operand
-			0xA0, // LDY immediate
-			0x04, //     Immediate operand
-			0x79, // ADC AbsoluteY
-			0x00, //     AbsoluteY operand
-			0x80, //     AbsoluteY operand
-			0xA2, // LDX immediate
-			0x05, //     Immediate operand
-			0x61, // ADC IndexedIndirectX
-			0x03, //     IndexedIndirectX operand
-			0xA0, // LDY immediate
-			0x10, //     Immediate operand
-			0x71, // ADC IndirectIndexedY
-			0x0F, //     IndirectIndexedY operand
-			0xEA, // NOP :)
-			0xFF, // Something invalid -- the end!
-		];
+        let program = [
+            // Code start
+            0xA9, // LDA Immediate
+            0x01, //     Immediate operand
+            0x69, // ADC Immediate
+            0x07, //     Immediate operand
+            0x65, // ADC ZeroPage
+            0x01, //     ZeroPage operand
+            0xA2, // LDX Immediate
+            0x01, //     Immediate operand
+            0x75, // ADC ZeroPageX
+            0x02, //     ZeroPageX operand
+            0x6D, // ADC Absolute
+            0x01, //     Absolute operand
+            0x80, //     Absolute operand
+            0xA2, // LDX immediate
+            0x08, //     Immediate operand
+            0x7D, // ADC AbsoluteX
+            0x00, //     AbsoluteX operand
+            0x80, //     AbsoluteX operand
+            0xA0, // LDY immediate
+            0x04, //     Immediate operand
+            0x79, // ADC AbsoluteY
+            0x00, //     AbsoluteY operand
+            0x80, //     AbsoluteY operand
+            0xA2, // LDX immediate
+            0x05, //     Immediate operand
+            0x61, // ADC IndexedIndirectX
+            0x03, //     IndexedIndirectX operand
+            0xA0, // LDY immediate
+            0x10, //     Immediate operand
+            0x71, // ADC IndirectIndexedY
+            0x0F, //     IndirectIndexedY operand
+            0xEA, // NOP :)
+            0xFF, // Something invalid -- the end!
+        ];
 
-		let data: [u8; 25] = [
-			0x00, 0x09, // ADC Absolute target
-			0x00, 0x00, 0x40, // ADC AbsoluteY target
-			0x00, 0x00, 0x00, 0x11, // ADC AbsoluteX target
-			0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x12, // ADC IndexedIndirectX target
-			0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x06, // ADC IndirectIndexedY target
-		];
+        let data: [u8; 25] = [
+            0x00, 0x09, // ADC Absolute target
+            0x00, 0x00, 0x40, // ADC AbsoluteY target
+            0x00, 0x00, 0x00, 0x11, // ADC AbsoluteX target
+            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x12, // ADC IndexedIndirectX target
+            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x06, // ADC IndirectIndexedY target
+        ];
 
-		// "Load" a program
-		cpu.memory.set_bytes(Address(0x0000), &zero_page_data);
-		cpu.memory.set_bytes(Address(0x4000), &program);
-		cpu.memory.set_bytes(Address(0x8000), &data);
+        // "Load" a program
+        cpu.memory.set_bytes(Address(0x0000), &zero_page_data);
+        cpu.memory.set_bytes(Address(0x4000), &program);
+        cpu.memory.set_bytes(Address(0x8000), &data);
 
-		cpu.registers.program_counter = Address(0x4000);
+        cpu.registers.program_counter = Address(0x4000);
 
-		cpu.run();
-	}
+        cpu.run();
+    }
 }