Reorganized folders, added pal-adapter io device folder

pat80-computer/software/z80-assembly/os/drivers/keyboard.asm

@@ -0,0 +1,56 @@
+; Keyboard driver
+; @author Daniele Verducci
+;
+; Requires declaration of following pointers, one for every column of the keys grid:
+; KEYB_A0_REG
+; KEYB_A1_REG
+; KEYB_A2_REG
+; KEYB_A3_REG
+; KEYB_A4_REG
+; These address must be exclusive if a decoder is not present.
+;
+; Example (no decoder):
+; KEYB_A0_REG = 0000001
+; KEYB_A1_REG = 0000010
+; KEYB_A2_REG = 0000100
+; KEYB_A3_REG = 0001000
+; etc...
+;
+; Example (with decoder):
+; KEYB_A0_REG = 0000000
+; KEYB_A1_REG = 0000001
+; KEYB_A2_REG = 0000010
+; KEYB_A3_REG = 0000011
+; etc...
+
+; Keyboard config (IO port 1)
+KEYB_A0_REG: EQU IO_1 + %00000001
+KEYB_A1_REG: EQU IO_1 + %00000010
+KEYB_A2_REG: EQU IO_1 + %00000100
+KEYB_A3_REG: EQU IO_1 + %00001000
+KEYB_A4_REG: EQU IO_1 + %00010000
+
+; Reads the keyboard
+; @return: a 0-terminated array of keycodes representing the pressed keys
+Keyb_read:
+    in a, (KEYB_A0_REG)
+    cp 0
+    jp z, _keyb_read_a1
+    add a, %01000000
+    call Lcd_printc     ; A already contains char to print
+    _loop:
+    in a, (KEYB_A0_REG)
+    cp 0
+    jp nz, _loop
+    ret
+    _keyb_read_a1:
+    in a, (KEYB_A1_REG)
+    cp 0
+    ret z
+    add a, %01010000
+    call Lcd_printc     ; A already contains char to print
+    _loop2:
+    in a, (KEYB_A1_REG)
+    cp 0
+    jp nz, _loop2
+    ret