Merge pull request #1 from GmEsoft/develop

Going public

.gitignore

@@ -30,3 +30,6 @@
 *.exe
 *.out
 *.app
+
+# Junk
+*.tws

README.md

@@ -1,2 +1,88 @@
 # Z80-MBC2_VGA32
-Z80-MBC2 Emulator running on TTGO ESP VGA32
+
+
+## Z80-MBC2 Emulator running on TTGO ESP VGA32
+
+This is a Z80-MBC2 emulator running on a TTGO ESP VGA32 board,
+an ESP32 device with a VGA connector, PS/2 keyboard and mouse
+connectors, an audio output jack and a Micro-SD card connector.
+
+This emulator runs a Z-80 processor at ca. 5.7 MHz (without throttling).
+The emulated Z80-MBC2 system is internally connected to the FABGL terminal,
+emulating an extended color ANSI terminal.
+
+It has a terminal configuration menu, accessible when the USER button is pressed
+on boot. The configuration menu has the following options:
+- `[D]isplay mode`: select the VGA resolution and color depth;
+- `[K]eyboard layout`: select an international keyboard layout;
+- `[T]ime settings`: automatic clock set-up on boot, via an Internet time server;
+- `[W]i-Fi settings`: select a Wi-Fi network, used to set the clock.
+
+The Z80-MBC2 configuration menu is also accessible using the USER button.
+The menu has been modified from the real Z80-MBC2 system:
+- `6: set Z80 clock speed`, changed to `6: Change user debug mode` - to invoke the simple
+  debugger by pressing the USER button while the emulated Z80 is running;
+- `9: change RTC time/date`, changed to `9: Change auto-boot mode` - to choose between
+  always invoking this menu on start-up or only via the USER button.
+
+
+## Build
+
+To build this sketch, the following items are needed:
+- Espressif ESP-32 hardware support tools and libraries for
+  the Arduino IDE, either integrated using the "Additional
+  Boards Manager URL":
+  <https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_dev_index.json>
+  or by cloning the GitHub repo or downloading the ZIP from
+  <https://github.com/espressif/arduino-esp32> (be sure to 
+  select the release branch "release/v1.0";
+- FabGL library from Fabrizio Di Vittorio from GitHub:
+  <https://github.com/fdivitto/FabGL.git> or my fork, which
+  also contains support for the Belgian keyboard layout:
+  <https://github.com/GmEsoft/FabGL.git>.
+
+In Arduino IDE v1.8.x, in Tools - Board:, select the "ESP32 Dev Module"
+board. In the configuration settings, select the following:
+- Partition Scheme: "Minimal SPIFFS (1.9MB APP with OTA/190KB SPIFFS)";
+- PSRAM: "Disabled".
+
+
+## Run
+
+To start this emulator, get a FAT32-formatted Micro-SD card, copy all files from
+the original Z80-MBC2 card image onto it, insert the card in the VGA32 module's
+SD connector. Connect a VGA monitor to the VGA blue connector, a PS/2 keyboard
+to the PS/2 purple connector, and an USB power supply to the Micro-USB connector.
+
+
+## Credits
+
+Thanks to the Z80-MBC2 Just4Fun project and its author SuperFabius - Fabio Defabis: 
+<https://hackaday.io/project/159973-z80-mbc2-a-4-ics-homebrew-z80-computer>
+and <https://github.com/SuperFabius/Z80-MBC2>.
+
+Also thanks to the FabGL library from Fabrizio Di Vittorio that turns an ESP32 
+embedded system into a smart VGA terminal with keyboard, mouse and audio output, 
+and a Micro-SD card slot: <https://github.com/fdivitto/FabGL>.
+
+
+## GPLv3 License
+
+Created by Michel Bernard ([email protected]) - <http://www.github.com/GmEsoft/Z80-MBC2_VGA32>
+Copyright (c) 2021 Michel Bernard.
+All rights reserved.
+
+This file is part of Z80-MBC2_VGA32.
+
+Z80-MBC2_VGA32 is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+Z80-MBC2_VGA32 is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with Z80-MBC2_VGA32.  If not, see <https://www.gnu.org/licenses/>.

Z80-MBC2_VGA32/Allocator.h

@@ -0,0 +1,180 @@
+/*
+    Z80-MBC2_VGA32 - Simple Memory Allocator
+      
+
+    Created by Michel Bernard ([email protected]) 
+    - <http://www.github.com/GmEsoft/Z80-MBC2_VGA32>
+    Copyright (c) 2021 Michel Bernard.
+    All rights reserved.
+    
+
+    This file is part of Z80-MBC2_VGA32.
+    
+    Z80-MBC2_VGA32 is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+    
+    Z80-MBC2_VGA32 is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+    
+    You should have received a copy of the GNU General Public License
+    along with Z80-MBC2_VGA32.  If not, see <https://www.gnu.org/licenses/>.
+
+*/
+
+#pragma once
+
+#include "log.h"
+
+#include "HardwareSerial.h"
+
+class Allocator
+{
+private:
+
+    enum Status
+    {
+        BOOKED = 0xA10CA7ED, // Allocated
+        FREE   = 0xF2EEF00D  // Free food
+    };
+
+    struct Header
+    {
+        Header  *prev_,
+                *next_;
+        size_t  size_;
+        int     status_;
+        //char    ptr_[0];
+    };
+
+public:
+
+    Allocator( void *pool, size_t size )
+    : pOrigin_( (Header*)pool ), initSize_( size )
+    {
+    }
+
+    void *malloc( size_t size )
+    {
+        if ( initSize_ )
+        {
+            pOrigin_->prev_ = pOrigin_->next_ = pOrigin_;
+            pOrigin_->size_ = initSize_ - sizeof( Header );
+            pOrigin_->status_ = FREE;
+            LOGD( "New allocator for size 0x%X at %p", pOrigin_->size_ , pOrigin_ );
+            debug( "Origin", pOrigin_ );
+            initSize_ = 0;
+        }
+
+        LOGD( "Allocating 0x%x bytes from pool %p", size, pOrigin_ );
+
+        Header *ptr = pOrigin_;
+        do {
+            ptr = ptr->prev_;
+
+            debug( "Candidate", ptr );
+
+            if ( ptr->status_ == FREE ) {
+                debug( "Free", ptr );
+                if( ptr->size_ >= size + sizeof( Header ) ) {
+                    debug( "Taking", ptr );
+                    Header *pNewFree = (Header*)( (char*)ptr + size + sizeof( Header ) );
+                    pNewFree->prev_ = ptr;
+                    pNewFree->next_ = ptr->next_;
+                    pNewFree->size_ = ptr->size_ - size - sizeof( Header );
+                    pNewFree->status_ = FREE;
+                    ptr->next_ = pNewFree;
+                    ptr->size_ = size;
+                    ptr->status_ = BOOKED;
+                    pOrigin_->prev_ = pNewFree;
+                    debug( "New", ptr );
+                    debug( "Prev", ptr->prev_ );
+                    debug( "Next", ptr->next_ );
+                    check();
+                    LOGD( "Returning %p", ptr + 1 );
+                    return (void*)( ptr + 1 );
+                }
+            } else if ( ptr->status_ != BOOKED ) {
+                LOGE( "ABEND! Memory Pool Corrupt at %p", ptr );
+                Serial.printf( "ABEND! Memory Pool Corrupt at %p", ptr );
+                for (;;);
+            }
+        } while( ptr != pOrigin_ );
+
+        return 0;  // malloc failed
+    }
+
+    void free( void *pFree )
+    {
+        Header *ptr = (Header*)pFree - 1;
+
+        if ( ptr->status_ == FREE ) {
+            LOGE( "ABEND! Already free pointer: %p", pFree );
+            Serial.printf( "ABEND! Already free pointer: %p", pFree );
+            for (;;);
+        } else if ( ptr->status_ != BOOKED ) {
+            LOGE( "ABEND! Memory Pool Corrupt at %p", ptr );
+            Serial.printf( "ABEND! Memory Pool Corrupt at %p", ptr );
+            for (;;);
+        }
+
+        ptr->status_ = FREE;
+        debug( "free", ptr );
+
+        // merge with next block if free
+        if ( ptr->next_ != pOrigin_ && ptr->next_->status_ == FREE ) {
+            LOGD( "Merging with next, deleting next" );
+            debug( "Delete", ptr->next_ );
+            ptr->next_ = ptr->next_->next_;
+            ptr->next_->prev_ = ptr;
+            ptr->size_ += ptr->next_->size_ + sizeof( Header );
+            debug( "Prev", ptr );
+            debug( "Next", ptr->next_ );
+        }
+
+        // merge with previous block if free
+        if ( ptr != pOrigin_ && ptr->prev_->status_ == FREE ) {
+            LOGD( "Merging with next, deleting this" );
+            debug( "Delete", ptr );
+            ptr->prev_->next_ = ptr->next_;
+            ptr->next_->prev_ = ptr->prev_;
+            ptr->prev_->size_ += ptr->size_ + sizeof( Header );
+            debug( "Prev", ptr->prev_ );
+            debug( "Next", ptr->next_ );
+        }
+
+        check();
+    }
+
+    void debug( const char *name, const Header *header )
+    {
+        LOGD( "%-10s: %p prev=%p next=%p size=0x%x status=%x", name, header, header->prev_, header->next_, header->size_, header->status_ );
+    }
+
+    void check()
+    {
+        LOGD( "Checking block chain" );
+        Header *ptr = pOrigin_;
+        int i = 0;
+        do {
+            String block( "Block " );
+            block += i;
+            debug( block.c_str(), ptr );
+            if ( ptr->next_->prev_ != ptr )
+                LOGE( "Error: ptr->next_->prev_ (=0x%x) != ptr (=0x%x)", ptr->next_->prev_, ptr );
+            if ( ptr->prev_->next_ != ptr )
+                LOGE( "Error: ptr->prev_->next_ (=0x%x) != ptr (=0x%x)", ptr->prev_->next_, ptr );
+            if ( ptr < ptr->next_ && ptr->status_ == FREE && ptr->next_->status_ == FREE )
+                LOGE( "Error: unmerged free blocks %p & %p", ptr, ptr->next_ );
+            ptr = ptr->next_;
+            ++i;
+        } while ( ptr != pOrigin_ );
+    }
+
+private:
+    Header  *pOrigin_;
+    size_t  initSize_;
+};