From ec720a908b757bf928101bef2178f67f38fff191 Mon Sep 17 00:00:00 2001
From: Alexander Tsidaev <a.tsidaev@gmail.com>
Date: Mon, 10 Nov 2014 18:40:08 +0500
Subject: [PATCH] zx128: keyboard support for tty

---
 Kernel/platform-zx128/devtty.c | 108 ++++++++++++++++++++++++++++++++-
 Kernel/platform-zx128/devtty.h |   1 +
 2 files changed, 108 insertions(+), 1 deletion(-)

diff --git a/Kernel/platform-zx128/devtty.c b/Kernel/platform-zx128/devtty.c
index 79f23005..c2d7713f 100644
--- a/Kernel/platform-zx128/devtty.c
+++ b/Kernel/platform-zx128/devtty.c
@@ -8,6 +8,41 @@
 
 char tbuf1[TTYSIZ];
 
+/* buffer for port scan procedure */
+uint8_t keybuf[8];
+/* keyboard state on previous execution. Initialized with all 0x1F (everything released) */
+uint8_t keymap[8] = { 0x1F, 0x1F, 0x1F, 0x1F, 0x1F, 0x1F, 0x1F, 0x1F };
+
+static uint8_t keybyte, keybit;
+static uint8_t newkey;
+static int keysdown = 0;
+
+static uint8_t keyboard[8][5] = {
+	{ ' ',  0,  'm', 'n', 'b' },
+	{  13, 'l', 'k', 'j', 'h',},
+	{ 'p', 'o', 'i', 'u', 'y',},
+	{ '0', '9', '8', '7', '6' },
+	{ '1', '2', '3', '4', '5' },
+	{ 'q', 'w', 'e', 'r', 't' },
+	{ 'a', 's', 'd', 'f', 'g' },
+	{  0,  'z', 'x', 'c', 'v' }
+};
+
+/* SYMBOL SHIFT MODE */
+static uint8_t keyboard_ss[8][5] = {
+	{ ' ',  0,  '.', ',', '*' },
+	{  13, '=', '+', '-', '^',},
+	{ '"', ';',  0 ,  0 ,  0 ,},
+	{ '_', ')', '(', '\'', '&' },
+	{ '!', '@', '#', '$', '%' },
+	{  0 ,  0 ,  0 , '<', '>' },
+	{  0 ,  0 ,  0 ,  0 ,  0  },
+	{  0,  ':',  0 , '?', '/' } /* 'x' key should actually contain British pound sign here if "big" font is used */
+};
+
+
+static uint8_t shiftmask[8] = { 0x02, 0, 0, 0, 0, 0, 0, 0x01 };
+
 struct s_queue ttyinq[NUM_DEV_TTY + 1] = {	/* ttyinq[0] is never used */
 	{NULL, NULL, NULL, 0, 0, 0},
 	{tbuf1, tbuf1, tbuf1, TTYSIZ, 0, TTYSIZ / 2},
@@ -47,15 +82,86 @@ void tty_setup(uint8_t minor)
 	minor;
 }
 
+void update_keyboard(void)
+{
+	/* We need this assembler code because SDCC __sfr cannot handle 16-bit addresses. And because it is much faster, of course  */
+	/* TODO: make it naked? */
+	__asm
+	ld hl, #_keybuf
+	ld c, #0xFE
+	ld b, #0x7f
+	ld e, #8        ; 8 keyboard ports, 7FFE, BFFE, DFFE and so on
+read_halfrow:
+	in a, (c)
+;	and #0
+	ld (hl), a
+	rrc b
+	inc hl
+	dec e
+	jr nz, read_halfrow
+	__endasm;
+}
+
 void tty_pollirq(void)
 {
+	int i;
+
+	update_keyboard();
+
+	newkey = 0;
+
+	for (i = 0; i < 8; i++) {
+		int n;
+		uint8_t m = 0x10;
+		for (n = 4; n >= 0; n--) {
+			if ((keybuf[i] & m) && !(keymap[i] & m))
+				if (!shiftmask[i] & m)
+					keysdown--;
+
+			if (!(keybuf[i] & m) && (keymap[i] & m)) {
+				if (!(shiftmask[i] & m))
+				    keysdown++;
+				keybyte = i;
+				keybit = n;
+				newkey = 1;
+			}
+			m >>= 1;
+		}
+		keymap[i] = keybuf[i];
+	}
 
+	if (keysdown < 3 && newkey)
+		keydecode();
 }
 
-void tty_interrupt(void)
+static void keydecode(void)
 {
+	uint8_t c;
+
+	uint8_t ss = !(keymap[0] & 0x02); /* SYMBOL SHIFT */
+	uint8_t cs = !(keymap[7] & 0x01); /* CAPS SHIFT */
+
+	if (ss)
+	{
+		c = keyboard_ss[keybyte][keybit];
+	}
+	else {
+		c = keyboard[keybyte][keybit];
+		if (cs)
+		{
+			if (c >= 'a' && c <= 'z')
+				c -= 'a' - 'A';
+			else if (c == '0') /* CS + 0 is backspace) */
+				c = 0x08;
+		}
+	}
+	
+
+	if (c != 0)
+		tty_inproc(1, c);
 }
 
+
 /* This is used by the vt asm code, but needs to live in the kernel */
 uint16_t cursorpos;
 
diff --git a/Kernel/platform-zx128/devtty.h b/Kernel/platform-zx128/devtty.h
index de0eaf73..f96542ff 100644
--- a/Kernel/platform-zx128/devtty.h
+++ b/Kernel/platform-zx128/devtty.h
@@ -2,5 +2,6 @@
 #define __DEVTTY_DOT_H__
 
 void tty_pollirq(void);
+static void keydecode(void);
 
 #endif
-- 
2.34.1