From 410c52a7c99c423e7327a9f8152628c906c0d82a Mon Sep 17 00:00:00 2001
From: BearOso <bearoso@gmail.com>
Date: Thu, 16 Mar 2023 14:42:23 -0500
Subject: [PATCH] SPC<-->DSP use two sets of registers.

---
 apu/bapu/dsp/SPC_DSP.cpp | 10 +++++++++-
 apu/bapu/dsp/SPC_DSP.h   |  5 ++++-
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/apu/bapu/dsp/SPC_DSP.cpp b/apu/bapu/dsp/SPC_DSP.cpp
index 6213b08b..06de2451 100644
--- a/apu/bapu/dsp/SPC_DSP.cpp
+++ b/apu/bapu/dsp/SPC_DSP.cpp
@@ -55,9 +55,11 @@ static BOOST::uint8_t const initial_regs [SPC_DSP::register_count] =
 
 // Access global DSP register
 #define REG(n)      m.regs [r_##n]
+#define XREG(n)     m.external_regs [r_##n]
 
 // Access voice DSP register
 #define VREG(r,n)   r [v_##n]
+#define XVREG(r,n)  (m.external_regs + (r - m.regs))[v_##n]
 
 #define WRITE_SAMPLES( l, r, out ) \
 {\
@@ -927,6 +929,7 @@ inline VOICE_CLOCK( V7 )
 {
 	// Update ENDX
 	REG(endx) = m.endx_buf;
+	XREG(endx) = m.endx_buf;
 
 	m.envx_buf = v->t_envx_out;
 }
@@ -934,11 +937,13 @@ inline VOICE_CLOCK( V8 )
 {
 	// Update OUTX
 	VREG(v->regs,outx) = m.outx_buf;
+	XVREG(v->regs,outx) = m.outx_buf;
 }
 inline VOICE_CLOCK( V9 )
 {
 	// Update ENVX
 	VREG(v->regs,envx) = m.envx_buf;
+	XVREG(v->regs,envx) = m.envx_buf;
 }
 
 // Most voices do all these in one clock, so make a handy composite
@@ -1237,7 +1242,9 @@ void SPC_DSP::soft_reset()
 
 void SPC_DSP::load( uint8_t const regs [register_count] )
 {
-	memcpy( m.regs, regs, sizeof m.regs );
+	memcpy( m.external_regs, regs, sizeof m.regs );
+	memset( m.regs, 0, sizeof m.regs);
+	m.regs[r_flg] = 0xE0;
 	memset( &m.regs [register_count], 0, offsetof (state_t,ram) - register_count );
 
 	// Internal state
@@ -1398,6 +1405,7 @@ void SPC_DSP::copy_state( unsigned char** io, copy_func_t copy )
 	SPC_COPY( uint16_t, m.t_echo_ptr );
 	SPC_COPY(  uint8_t, m.t_looped );
 
+	copier.copy(m.external_regs, register_count);
 	copier.extra();
 }
 #endif
diff --git a/apu/bapu/dsp/SPC_DSP.h b/apu/bapu/dsp/SPC_DSP.h
index bea8ec03..953b13bf 100644
--- a/apu/bapu/dsp/SPC_DSP.h
+++ b/apu/bapu/dsp/SPC_DSP.h
@@ -204,6 +204,8 @@ private:
 		sample_t extra [extra_size];
 
         uint8_t separate_echo_buffer [0x10000];
+		uint8_t external_regs [register_count];
+
 	};
 	state_t m;
 
@@ -260,7 +262,7 @@ inline int SPC_DSP::sample_count() const { return m.out - m.out_begin; }
 inline int SPC_DSP::read( int addr ) const
 {
 	assert( (unsigned) addr < register_count );
-	return m.regs [addr];
+	return m.external_regs [addr];
 }
 
 inline void SPC_DSP::write( int addr, int data )
@@ -268,6 +270,7 @@ inline void SPC_DSP::write( int addr, int data )
 	assert( (unsigned) addr < register_count );
 
 	m.regs [addr] = (uint8_t) data;
+	m.external_regs [addr] = (uint8_t) data;
 	switch ( addr & 0x0F )
 	{
 	case v_envx: