From 0a2d4a256da6f5858e3fcdbd45e150536a9d3a56 Mon Sep 17 00:00:00 2001
From: couriersud <couriersud@gmx.org>
Date: Sat, 27 May 2017 22:13:52 +0200
Subject: [PATCH] Fix issues identified by Vas and LordKale4:

- made local netlists in Cheeky Mouse static
- replace stdlib rand by 16 bit galois lfsr

(nw)
---
 src/lib/netlist/devices/nlid_proxy.cpp |  1 +
 src/lib/netlist/plib/pfunction.cpp     |  3 +--
 src/lib/netlist/plib/pfunction.h       | 12 ++++++++++++
 src/mame/audio/nl_cheekyms.cpp         |  4 ++--
 4 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/src/lib/netlist/devices/nlid_proxy.cpp b/src/lib/netlist/devices/nlid_proxy.cpp
index c71e9f2919e..4c3ec6f67aa 100644
--- a/src/lib/netlist/devices/nlid_proxy.cpp
+++ b/src/lib/netlist/devices/nlid_proxy.cpp
@@ -121,6 +121,7 @@ namespace netlist
 				f = true;
 			}
 		}
+		//FIXME: Use power terminals!
 		if (!f)
 			log().warning(MW_1_NO_POWER_TERMINALS_ON_DEVICE_1, out_proxied->device().name());
 		else
diff --git a/src/lib/netlist/plib/pfunction.cpp b/src/lib/netlist/plib/pfunction.cpp
index 42f767ef562..a1cfb8f3366 100644
--- a/src/lib/netlist/plib/pfunction.cpp
+++ b/src/lib/netlist/plib/pfunction.cpp
@@ -12,7 +12,6 @@
 
 #include <cmath>
 #include <stack>
-#include <stdlib.h>
 
 namespace plib {
 
@@ -204,7 +203,7 @@ double pfunction::evaluate(const std::vector<double> &values)
 			OP(SIN,  0, std::sin(ST2));
 			OP(COS,  0, std::cos(ST2));
 			case RAND:
-				stack[ptr++] = static_cast<double>(rand()) / static_cast<double>(RAND_MAX);
+				stack[ptr++] = lfsr_random();
 				break;
 			case PUSH_INPUT:
 				stack[ptr++] = values[static_cast<unsigned>(rc.m_param)];
diff --git a/src/lib/netlist/plib/pfunction.h b/src/lib/netlist/plib/pfunction.h
index 50e279cf034..58f47904b62 100644
--- a/src/lib/netlist/plib/pfunction.h
+++ b/src/lib/netlist/plib/pfunction.h
@@ -44,6 +44,7 @@ namespace plib {
 		};
 	public:
 		pfunction()
+		: m_lfsr(0xACE1u)
 		{
 		}
 
@@ -79,7 +80,18 @@ namespace plib {
 		void compile_postfix(const std::vector<pstring> &inputs,
 				const std::vector<pstring> &cmds, const pstring &expr);
 
+		double lfsr_random()
+		{
+			std::uint16_t lsb = m_lfsr & 1;
+		    m_lfsr >>= 1;
+		    if (lsb)
+		    	m_lfsr ^= 0xB400u; // taps 15, 13, 12, 10
+		    return static_cast<double>(m_lfsr) / static_cast<double>(0xffffu);
+		}
+
 		std::vector<rpn_inst> m_precompiled; //!< precompiled expression
+
+		std::uint16_t m_lfsr; //!< lfsr used for generating random numbers
 	};
 
 
diff --git a/src/mame/audio/nl_cheekyms.cpp b/src/mame/audio/nl_cheekyms.cpp
index cb93a6b6b72..6caaf71d610 100644
--- a/src/mame/audio/nl_cheekyms.cpp
+++ b/src/mame/audio/nl_cheekyms.cpp
@@ -41,7 +41,7 @@
  * there is nothing to amplify currently.
  */
 
-NETLIST_START(cheekyms_schematics)
+static NETLIST_START(cheekyms_schematics)
 
 	// Shared chips
 	TTL_7404_DIP(IC1)
@@ -239,7 +239,7 @@ NETLIST_END()
  *
  */
 
-NETLIST_START(NOISE)
+static NETLIST_START(NOISE)
 	CS(FC, 0)
 	PARAM(FC.FUNC, "0.0000001 rand *")