From a2739c054c27f6bf62498a7a2fc5f77917928350 Mon Sep 17 00:00:00 2001
From: Keith Bourdon <33245078+celerizer@users.noreply.github.com>
Date: Tue, 15 Oct 2024 15:03:29 -0500
Subject: [PATCH] start working on lcd commands

---
 devices/lcd.c | 173 ++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 169 insertions(+), 4 deletions(-)

diff --git a/devices/lcd.c b/devices/lcd.c
index a92ce8c..6521c49 100644
--- a/devices/lcd.c
+++ b/devices/lcd.c
@@ -1,14 +1,56 @@
 #include "../dma.h"
 #include "lcd.h"
+#include "../types.h"
 
 static const char *name = "128x64 LCD device";
 static const h8_device_id type = H8_DEVICE_LCD;
 
+typedef union
+{
+  H8_BITFIELD_4
+  (
+    /** Hardcoded chip ID */
+    h8_u8 id : 4,
+
+    /** Whether the device is busy with a reset. Unimplemented */
+    h8_u8 res : 1,
+
+    /** Whether the device is on */
+    h8_u8 on : 1,
+
+    /** Whether the device is busy with a command. Unimplemented */
+    h8_u8 bsy : 1
+  ) flags;
+  h8_u8 raw;
+} h8_lcd_sr_t;
+
 typedef struct
 {
   h8_u8 vram[128 * 64];
   h8_bool selected;
   h8_bool mode;
+  h8_u8 command;
+  h8_bool second_byte;
+
+  h8_u8 x, y;
+
+  /** @todo What is this? */
+  h8_bool icon_enable;
+
+  /** If true, displays all pixels on regardless of VRAM contents */
+  h8_bool all_on;
+
+  h8_bool inverse_display;
+
+  h8_bool power_save;
+
+  /** If true, the display will sleep when power save is enabled.
+   *  If false, the display will standby. */
+  h8_bool power_save_mode_sleep;
+
+  h8_bool x_flip, y_flip;
+
+  h8_lcd_sr_t status;
 } h8_lcd_t;
 
 #define H8_LCD_MODE_CMD 0
@@ -32,16 +74,136 @@ void h8_lcd_read(h8_device_t *device, h8_byte_t *dst)
 {
   h8_lcd_t *m_lcd = device->device;
 
-  /** @todo */
-  dst->u = m_lcd->vram[0];
+  if (m_lcd->mode)
+    dst->u = m_lcd->status.raw;
+  else
+    /** @todo */
+    dst->u = 0;
 }
 
 void h8_lcd_write(h8_device_t *device, h8_byte_t *dst, const h8_byte_t value)
 {
   h8_lcd_t *m_lcd = device->device;
 
-  /** @todo */
-  m_lcd->vram[0] = value.u;
+  if (!m_lcd->second_byte)
+  {
+    m_lcd->command = value.u;
+    switch (m_lcd->command)
+    {
+    /** Set Column Address bit0-3 */
+    case 0x00:
+    case 0x01:
+    case 0x02:
+    case 0x03:
+    case 0x04:
+    case 0x05:
+    case 0x06:
+    case 0x07:
+    case 0x08:
+    case 0x09:
+    case 0x0A:
+    case 0x0B:
+    case 0x0C:
+    case 0x0D:
+    case 0x0E:
+    case 0x0F:
+      m_lcd->x = (m_lcd->x & B01110000) | value.u;
+      break;
+    /** Set Column Address bit4-6 */
+    case 0x10:
+    case 0x11:
+    case 0x12:
+    case 0x13:
+    case 0x14:
+    case 0x15:
+    case 0x16:
+    case 0x17:
+      m_lcd->x = (m_lcd->x & B00001111) | ((value.u & B00000111) << 4);
+      break;
+    case 0xA2:
+      m_lcd->icon_enable = FALSE;
+      break;
+    case 0xA3:
+      m_lcd->icon_enable = TRUE;
+      break;
+    case 0xA4:
+      m_lcd->status.flags.on = FALSE;
+      break;
+    case 0xA5:
+      m_lcd->status.flags.on = TRUE;
+      break;
+    case 0xA6:
+      m_lcd->inverse_display = FALSE;
+      break;
+    case 0xA7:
+      m_lcd->inverse_display = TRUE;
+      break;
+    case 0xA8:
+      m_lcd->power_save_mode_sleep = FALSE;
+      break;
+    case 0xA9:
+      m_lcd->power_save_mode_sleep = TRUE;
+      break;
+    case 0xB0:
+    case 0xB1:
+    case 0xB2:
+    case 0xB3:
+    case 0xB4:
+    case 0xB5:
+    case 0xB6:
+    case 0xB7:
+    case 0xB8:
+    case 0xB9:
+    case 0xBA:
+    case 0xBB:
+    case 0xBC:
+    case 0xBD:
+    case 0xBE:
+    case 0xBF:
+      m_lcd->y = (value.u & B00001111) * 8;
+      break;
+    case 0xC0:
+    case 0xC1:
+    case 0xC2:
+    case 0xC3:
+    case 0xC4:
+    case 0xC5:
+    case 0xC6:
+    case 0xC7:
+      m_lcd->y_flip = FALSE;
+      break;
+    case 0xC8:
+    case 0xC9:
+    case 0xCA:
+    case 0xCB:
+    case 0xCC:
+    case 0xCD:
+    case 0xCE:
+    case 0xCF:
+      m_lcd->y_flip = TRUE;
+      break;
+    case 0xE1:
+      m_lcd->power_save = FALSE;
+      break;
+    /** Software Reset */
+    case 0xE2:
+      /** @todo set defaults */
+      break;
+    default:
+      break;
+    }
+  }
+  else
+  {
+    switch (m_lcd->command)
+    {
+    default:
+      break;
+    }
+    m_lcd->second_byte = FALSE;
+  }
+
+  *dst = value;
 }
 
 void h8_lcd_init(h8_device_t *device)
@@ -50,6 +212,9 @@ void h8_lcd_init(h8_device_t *device)
   {
     h8_lcd_t *m_lcd = h8_dma_alloc(sizeof(h8_lcd_t), TRUE);
 
+    m_lcd->status.flags.on = TRUE;
+    m_lcd->status.flags.id = 0x08;
+
     device->device = m_lcd;
     device->read = h8_lcd_read;
     device->write = h8_lcd_write;