From 267f9b676f8fb9c397036b9428380ecd6619f899 Mon Sep 17 00:00:00 2001
From: Alan Cox <alan@linux.intel.com>
Date: Sat, 8 Sep 2018 01:07:41 +0100
Subject: [PATCH] plato: draft trs80 hrg

---
 Applications/plato/tgi_trs80_hg.c | 132 ++++++++++++++++++++++++++++++
 1 file changed, 132 insertions(+)
 create mode 100644 Applications/plato/tgi_trs80_hg.c

diff --git a/Applications/plato/tgi_trs80_hg.c b/Applications/plato/tgi_trs80_hg.c
new file mode 100644
index 00000000..44db6a23
--- /dev/null
+++ b/Applications/plato/tgi_trs80_hg.c
@@ -0,0 +1,132 @@
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/graphics.h>
+#include "tgi.h"
+
+/*
+ *	Most of this should be asm
+ */
+
+static uint8_t pen;
+
+__sfr __at 0x80 gfx_x;
+__sfr __at 0x81 gfx_y;
+__sfr __at 0x82 gfx_d;
+__sfr __at 0x83 gfx_ctrl;
+
+static struct display d;
+static struct videomap vm;
+
+void tgi_init(void)
+{
+
+    /* FIXME: need to scan modes then call the right thing */
+
+    if (ioctl(0, GFXIOC_GETINFO, &d) == -1)
+        bad();
+    if (d.format != FMT_MONO_WB || d.hardware != HW_TRS80GFX)
+        bad();
+    if (ioctl(0, GFXIOC_MAP, &vm) == -1)
+        bad();
+    if (vm.pio != (void *)0x80)
+        bad();
+    trs80_ctrl = 0xF3;
+}
+
+/* Needs to get called on atexit case */
+void tgi_done(void)
+{
+    ioctl(0, GFXIOC_UNMAP, &vm);
+    /* and put old mode back FIXME */
+    
+}
+
+void tgi_setpalette(const unsigned char *palette)
+{
+}
+
+void tgi_clear(void)
+{
+    gfx_
+}
+
+void tgi_setcolor(unsigned char c)
+{
+  pen = c;
+}
+
+static uint8_t bit[8] = { 128, 64, 32, 16, 8, 4, 2, 1 };
+
+void tgi_setpixel(int x, int y)
+{
+    uint8_t bit = bit[x & 7];
+    trs80_x = x >> 3;
+    trs80_y = y;
+    if (pen)
+        trs80_d = trs80_d | bit;
+    else
+        trs80_d = trs80_d & ~bit;
+}
+
+void tgi_bar(int x1, int y1, int x2, int y2)
+{
+  int x,y;
+  uint8_t lm = x1 & 7;
+  uint8_t rm = x2 & 7;
+  x1 >> = 3;
+  x2 >> = 3;
+  if (x1 == x2) {
+      trs80_ctrl = 0x73;	/* Clock Y up */
+      lm &= rm;
+      if (pen) {
+          for (y = y1; y < y2; y++)
+              trs80_d |= rm;
+      } else {
+          rm =~ rm;
+          for (y = y1; y < y2; y++)
+              trs80+d &= rm;
+      }
+      trs80_ctrl = 0xF3;
+      return;
+  }
+  trs80_ctrl = 0xB3;		/* Clock X */
+  if (pen) {
+      for (y = y1; y < y2; y++) {
+          trs80_y = y;
+          trs80_x = x1;
+          trs80_d |= lm;
+          for (x = x1 + 1; x < x2; x++)
+              trs80_d = 0xFF;
+          trs80_d |= rm;
+      }
+  } else {
+      lm = ~lm;
+      rm = ~rm;
+      for (y = y1; y < y2; y++) {
+          trs80_y = y;
+          trs80_x = x1;
+          trs80_d &= lm;
+          for (x = x1 + 1; x < x2; x++)
+              trs80_d = 0x00;
+          trs80_d &= rm;
+      }
+  }
+}
+
+void tgi_line(int x1, int y1, int x2, int y2)
+{
+   int dx =  abs(x2-x1), sx = x1<x2 ? 1 : -1;
+   int dy = -abs(y2-y1), sy = y1<y2 ? 1 : -1; 
+   int err = dx+dy, e2; /* error value e_xy */
+ 
+   for(;;){  /* loop */
+      /* FIXME: use an optimized setpixel that spots re-writing the same
+         byte */
+      tgi_setpixel(x1,y1);
+      if (x1==x2 && y1==y2) break;
+      e2 = 2*err;
+      if (e2 >= dy) { err += dy; x1 += sx; } /* e_xy+e_x > 0 */
+      if (e2 <= dx) { err += dx; y1 += sy; } /* e_xy+e_y < 0 */
+   }
+}
-- 
2.34.1