Apple-2-SW/apple2a
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Simple line input.

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This commit is contained in:
Lawrence Kesteloot 2018-07-31 12:48:29 -07:00
parent 1756190e0c
commit d5ede1617d
1 changed files with 98 additions and 13 deletions
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111
main.c
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@ -3,6 +3,18 @@
char *title = "Apple IIa";
unsigned char title_length = 9;
#define CURSOR_GLYPH 127
#define SCREEN_WIDTH 40
#define SCREEN_STRIDE (3*SCREEN_WIDTH + 8)
// Location of cursor in logical screen space.
unsigned int cursor_x = 0;
unsigned int cursor_y = 0;
// Whether the cursor is being displayed.
unsigned int showing_cursor = 0;
// Character at the cursor location.
unsigned char cursor_ch = 0;
/**
* Delay for a count of "t". 8000 is about one second.
*/
@ -21,11 +33,54 @@ static void home() {
int i;
// TODO: Could write these as words, not chars.
for (i = (40 + 40 + 48)*8; i >= 0; i--) {
for (i = SCREEN_STRIDE*8; i >= 0; i--) {
*p++ = ch;
}
}
/**
* Return the memory location of the cursor.
*/
static volatile unsigned char *cursor_pos() {
int block = cursor_y >> 3;
int line = cursor_y & 0x07;
return TEXT_PAGE1_BASE + line*SCREEN_STRIDE + block*SCREEN_WIDTH + cursor_x;
}
/**
* Shows the cursor. Safe to call if it's already showing.
*/
static void show_cursor() {
if (!showing_cursor) {
volatile unsigned char *pos = cursor_pos();
cursor_ch = *pos;
*pos = CURSOR_GLYPH | 0x80;
showing_cursor = 1;
}
}
/**
* Hides the cursor. Safe to call if it's not already shown.
*/
static void hide_cursor() {
if (showing_cursor) {
volatile unsigned char *pos = cursor_pos();
*pos = cursor_ch;
showing_cursor = 0;
}
}
/**
* Moves the cursor to the specified location, where X
* is 0 to 39 inclusive, Y is 0 to 23 inclusive.
*/
static void move_cursor(int x, int y) {
hide_cursor();
cursor_x = x;
cursor_y = y;
}
int main(void)
{
int offset = (40 - title_length) / 2;
@ -42,22 +97,52 @@ int main(void)
}
// Prompt.
loc = TEXT_PAGE1_BASE + (40 + 40 + 48)*2;
*loc++ = ']' | 0x80;
move_cursor(0, 2);
loc = cursor_pos();
*loc = ']' | 0x80;
move_cursor(cursor_x + 1, cursor_y);
// Cursor.
i = 1;
// Keyboard input.
i = 0;
show_cursor();
while(1) {
*loc = 127 | 0x80;
delay(2500);
*loc = ' ' | 0x80;
delay(2500);
// Blink cursor.
i += 1;
if (i == 2000) {
if (showing_cursor) {
hide_cursor();
} else {
show_cursor();
}
i = 0;
}
while(keyboard_test()) {
unsigned char key;
if(keyboard_test()) {
hide_cursor();
key = keyboard_get();
loc[i++] = key | 0x80;
while(keyboard_test()) {
unsigned char key;
key = keyboard_get();
if (key == 8) {
// Backspace.
if (cursor_x > 1) {
move_cursor(cursor_x - 1, cursor_y);
}
} else if (key == 13) {
// Return.
move_cursor(0, cursor_y + 1);
loc = cursor_pos();
*loc = ']' | 0x80;
move_cursor(cursor_x + 1, cursor_y);
} else {
volatile unsigned char *loc = cursor_pos();
*loc = key | 0x80;
move_cursor(cursor_x + 1, cursor_y);
}
}
show_cursor();
}
}