From 3a20bc6fcef5c97def6fbdd2ecd0f0a0a5a3782e Mon Sep 17 00:00:00 2001
From: hap <happppp@users.noreply.github.com>
Date: Tue, 23 Feb 2021 16:46:05 +0100
Subject: [PATCH] hh_cops1: qkracerm ram is 8x12

---
 src/devices/cpu/cops1/cops1base.cpp | 2 ++
 src/devices/cpu/cops1/mm5799.cpp    | 5 ++++-
 src/mame/drivers/hh_cops1.cpp       | 2 +-
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/devices/cpu/cops1/cops1base.cpp b/src/devices/cpu/cops1/cops1base.cpp
index 08f882df59c..540724e61c2 100644
--- a/src/devices/cpu/cops1/cops1base.cpp
+++ b/src/devices/cpu/cops1/cops1base.cpp
@@ -25,6 +25,8 @@ TODO:
 - documentation says that LB 10 is either 0 or 4, depending on RAM configuration,
   but on qkracerm it's 5 (also confirmed in patent source code), so I assume
   LB 10 is fully configurable as mask option
+- MM5799 RAM layout is derived from MCU decap, documentation suggests that the
+  secondary option is literally 6x16 but according to the decap it's 4x16 + 4x8
 
 */
 
diff --git a/src/devices/cpu/cops1/mm5799.cpp b/src/devices/cpu/cops1/mm5799.cpp
index bffb5e64a66..7ea0ce4a1ff 100644
--- a/src/devices/cpu/cops1/mm5799.cpp
+++ b/src/devices/cpu/cops1/mm5799.cpp
@@ -29,11 +29,14 @@ void mm5799_device::data_map(address_map &map)
 		// 8x12x4
 		for (int i = 0; i < 0x80; i += 0x10)
 			map(i | 0x04, i | 0x0f).ram();
+		map(0x00, 0x03).mirror(0x70).noprw();
 	}
 	else
 	{
 		// 6x16x4
-		map(0x00, 0x5f).ram();
+		map(0x00, 0x3f).ram();
+		for (int i = 0x40; i < 0x80; i += 0x10)
+			map(i | 0x00, i | 0x07).ram().mirror(0x08);
 	}
 }
 
diff --git a/src/mame/drivers/hh_cops1.cpp b/src/mame/drivers/hh_cops1.cpp
index b83b1931fcc..e5d87f8fa3e 100644
--- a/src/mame/drivers/hh_cops1.cpp
+++ b/src/mame/drivers/hh_cops1.cpp
@@ -8,7 +8,6 @@
   MCU die label for MM5799 games says MM4799, but they are in fact MM5799.
 
   TODO:
-  - qkracerm RAM configuration is unknown (it also works fine with 8x12)
   - qkracerm link cable
 
 ***************************************************************************/
@@ -399,6 +398,7 @@ void qkracerm_state::qkracerm(machine_config &config)
 {
 	/* basic machine hardware */
 	MM5799(config, m_maincpu, 220000); // approximation
+	m_maincpu->set_option_ram_d12(true);
 	m_maincpu->set_option_lb_10(5);
 	m_maincpu->write_do().set(FUNC(qkracerm_state::write_do));
 	m_maincpu->write_s().set(FUNC(qkracerm_state::write_s));