diff --git a/cpu.h b/cpu.h
index 44b03b8..7bb5035 100644
--- a/cpu.h
+++ b/cpu.h
@@ -5,6 +5,8 @@
 #include <setjmp.h>
 #endif
 
+#undef PC
+
 class CPU: public Checkpointable {
 public:
 	virtual void run(unsigned instructions) =0;
@@ -22,6 +24,7 @@ public:
 protected:
 	CPU (Memory &mem, jmp_buf &e, statfn s): _mem(mem), _err(e), _status(s), _debug(false) {}
 	Memory &_mem;
+	Memory::address PC;
 	jmp_buf &_err;
 	statfn _status;
 	bool _debug;
diff --git a/hardware.h b/hardware.h
index 111ff4a..8c017be 100644
--- a/hardware.h
+++ b/hardware.h
@@ -27,7 +27,7 @@
 //#define SPIRAM_CS       PF_3
 #define SPIRAM_SPI      1
 #define SPIRAM_DEV      SPI_for_SD
-#define SPIRAM_SIZE	32768
+#define SPIRAM_SIZE	65536
 
 // "tape" storage...
 #define SD_CS		PF_3
diff --git a/i8080.cpp b/i8080.cpp
index 6eb4c46..22c8b30 100644
--- a/i8080.cpp
+++ b/i8080.cpp
@@ -2,6 +2,7 @@
 
 #include "memory.h"
 #include "cpu.h"
+#include "ports.h"
 #include "i8080.h"
 
 #define CPU_STATE_FMT "%04x %02x %02x %04x %04x %04x %04x %d%d%d%d%d%d%d%d\r",\
@@ -117,7 +118,7 @@ int i8080::parity_table[] = {
 	1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
 };
 
-i8080::i8080(Memory &m, jmp_buf &jb, CPU::statfn s, Ports &d): CPU(m, jb, s)
+i8080::i8080(Memory &m, jmp_buf &jb, CPU::statfn s, PortDevice<i8080> &d): CPU(m, jb, s)
 {
 	_ports = &d;
 
diff --git a/i8080.h b/i8080.h
index 63de916..74dc8d8 100644
--- a/i8080.h
+++ b/i8080.h
@@ -6,14 +6,7 @@
 
 class i8080: public CPU {
 public:
-
-	class Ports {
-	public:
-		virtual void out(byte p, byte v, i8080 *cpu) =0;
-		virtual byte in(byte p, i8080 *cpu) =0;
-	};
-
-	i8080(Memory &, jmp_buf &, CPU::statfn, Ports &);
+	i8080(Memory &, jmp_buf &, CPU::statfn, PortDevice<i8080> &);
 
 	void run(unsigned);
 	void reset();
@@ -51,7 +44,7 @@ private:
 		struct { byte L, H; };
 		word HL;
 	};
-	Memory::address PC, SP;
+	Memory::address SP;
 	union {
 		struct {
 			unsigned C:1;
@@ -66,7 +59,7 @@ private:
 		byte SR;
 	};
 	int _irq_pending;
-	Ports *_ports;
+	PortDevice<i8080> *_ports;
 
 	typedef void (i8080::*OP)(); 
 	OP _ops[256];
@@ -322,7 +315,8 @@ private:
 	inline void _and(byte b) {
 		A = A & b;
 		_szp(A);
-		flags.C = flags.H = 0;
+		flags.C = 0;
+		flags.H = 1;
 	}
 
 	void anab() { _and(B); }
diff --git a/ports.h b/ports.h
new file mode 100644
index 0000000..127a352
--- /dev/null
+++ b/ports.h
@@ -0,0 +1,11 @@
+#ifndef __PORTS_H__
+#define __PORTS_H__
+
+template<class P>
+class PortDevice {
+public:
+	virtual void out(word p, byte v, P *cpu) =0;
+	virtual byte in(word p, P *cpu) =0;
+};
+
+#endif
diff --git a/r6502.h b/r6502.h
index 19dfd0e..a0aa1cd 100644
--- a/r6502.h
+++ b/r6502.h
@@ -16,7 +16,6 @@ public:
 	r6502 (Memory &, jmp_buf &, CPU::statfn);
 private:
 	/* registers */
-	Memory::address PC;
 	byte S, A, X, Y;
 	byte N, V, B, D, I, Z, C;
 	union {
diff --git a/spiram.cpp b/spiram.cpp
index 843527d..792b255 100644
--- a/spiram.cpp
+++ b/spiram.cpp
@@ -21,7 +21,7 @@ spiram::operator byte()
 void spiram::checkpoint(Stream &s)
 {
 	byte buf[Memory::page_size];
-	for (int i = 0; i < pages(); i++) {
+	for (unsigned i = 0; i < pages(); i++) {
 		spiRam.read_stream(i * 256, buf, sizeof(buf));
 		s.write(buf, sizeof(buf));
 	}
@@ -30,7 +30,7 @@ void spiram::checkpoint(Stream &s)
 void spiram::restore(Stream &s)
 {
 	byte buf[Memory::page_size];
-	for (int i = 0; i < pages(); i++) {
+	for (unsigned i = 0; i < pages(); i++) {
 		s.readBytes((char *)buf, sizeof(buf));
 		spiRam.write_stream(i * 256, buf, sizeof(buf));
 	}