1 files changed, 84 insertions, 0 deletions
diff --git a/sw-old/z80/drivers/pio.c b/sw-old/z80/drivers/pio.c
new file mode 100644
index 0000000..f396e43
--- /dev/null
+++ b/sw-old/z80/drivers/pio.c
@@ -0,0 +1,84 @@
+#include "pio.h"
+
+#ifdef PIO_ASM_INTERFACE
+// TODO: set inline
+void _pio_write(uint8_t reg, uint8_t data)
+{
+    __asm
+    ;;  pop function arguments data in h, reg in a (l)
+    pop hl
+    ld a, l
+    ;; add ADDR_DEV_PIO to get the device address
+    add a, #ADDR_DEV_PIO
+    ld c, a
+    ;; load data
+    out (c), h
+    __endasm;
+}
+
+inline uint8_t _pio_read(uint8_t reg)
+{
+    // TODO: check "dec sp"
+    __asm
+    ;; pop function argument
+    dec sp
+    pop hl
+    ld a, l
+    ;; add ADDR_DEV_PIO to get the device address
+    add a, #ADDR_DEV_PIO
+    ld c, a
+    ;; read data
+    in l, (c)
+    ret
+    __endasm;
+}
+
+#else
+
+inline void _pio_write(uint8_t reg, uint8_t data)
+{
+    *((uint8_t *) (ADDR_DEV_PIO + reg)) = data;
+}
+
+inline uint8_t _pio_read(uint8_t reg)
+{
+    return *((uint8_t *) (ADDR_DEV_PIO + reg));
+}
+
+#endif
+
+void pio_set_mode(int port, int mode, uint8_t io)
+{
+    // 0x0F is a control sequence to set mode
+    _pio_write((PIO_REG_CTRL + port), ((mode << 6) | 0x0F));
+
+    // this mode requires an additional argument that sets
+    // a mode for each pin
+    if (mode == PIO_MODE_BIT_IO) {
+        _pio_write((PIO_REG_CTRL + port), io);
+    }
+}
+
+void pio_set_interrupts(int port, int control)
+{
+    // 0x07 is a control sequence to set interrupts
+    _pio_write((PIO_REG_CTRL + port), (control<<4 | 0x07));
+}
+
+void pio_set_interrupts_mask(int port, int control, uint8_t mask)
+{
+    // 0x17 is a control sequence to set interrupts
+    // AND interpret the next byte as a bitmask
+    _pio_write((PIO_REG_CTRL + port),(control | 0x97));
+    _pio_write((PIO_REG_CTRL + port), mask);
+}
+
+uint8_t pio_read(int port)
+{
+    return _pio_read((PIO_REG_DATA + port));
+}
+
+void pio_write(int port, uint8_t data)
+{
+    _pio_write((PIO_REG_DATA + port), data);
+}