Init rtc and pic in kernel

sw/kernel/devices/interrupt_controller.h

@@ -0,0 +1,32 @@
+#ifndef _INTERRUPT_CONTROLLER_H
+#define _INTERRUPT_CONTROLLER_H
+
+#include <stdint.h>
+
+// These need to be copied in interrupt_controller.s
+
+#define IRQ_CMD_ADDR 0xeffc
+#define IRQ_DAT_ADDR 0xeffd
+
+#define IRQ_CMD_MASK 0xe0
+#define IRQ_REG_MASK 0x1f
+
+#define IRQ_CMD_READIRQ 0x00
+#define IRQ_CMD_ENABLE 0x20
+#define IRQ_CMD_TYPE 0x40
+#define IRQ_CMD_EOI 0xff
+
+#define IRQ_EDGE 0
+#define IRQ_LEVEL 1
+
+
+
+void init_interrupt_controller();
+
+void enable_irq(uint8_t type, uint8_t irqnum);
+void disable_irq(uint8_t irqnum);
+
+// This should accept irqnum later.
+void send_eoi();
+
+#endif

sw/kernel/devices/interrupt_controller.s

@@ -0,0 +1,136 @@
+.MACPACK generic
+
+.autoimport
+
+.importzp tmp1, tmp2
+
+.export _init_interrupt_controller
+.export _enable_irq
+.export _disable_irq
+.export _send_eoi
+
+IRQ_CMD_ADDR    = $effc
+IRQ_DAT_ADDR    = $effd
+
+IRQ_CMD_MASK    = $e0
+IRQ_REG_MASK    = $1f
+IRQ_CMD_READIRQ = $00
+IRQ_CMD_ENABLE  = $20
+IRQ_CMD_TYPE    = $40
+IRQ_CMD_EOI     = $ff
+
+.code
+
+; void init_irq();
+; mask all IRQs, set all type to edge.
+.proc _init_interrupt_controller
+    ldx #$20    ; enable
+    ldy #$ff
+    jsr cmd_all
+    ldx #$40    ; edge type
+    ldy #$00
+    jsr cmd_all
+    rts
+
+cmd_all:        ; Send the same value to all 32 bytes
+    txa
+    add #$20
+    sta tmp1
+loop:
+    txa
+    sta IRQ_CMD_ADDR
+    tya
+    sta IRQ_DAT_ADDR
+    inx
+    cpx tmp1
+    blt loop
+    rts
+.endproc
+
+
+; void enable_irq(uint8_t type, uint8_t irqnum);
+; in A: 
+.proc _enable_irq
+    ; Decide which byte we need to modify by dividing by 32 (>> 5)
+    pha
+    lsr
+    lsr
+    lsr
+    lsr
+    lsr         ; A is now bytesel
+    sta tmp2    ; tmp2 is now bytesel
+    add #IRQ_CMD_ENABLE
+    sta IRQ_CMD_ADDR
+    lda IRQ_DAT_ADDR
+    sta tmp1
+    pla
+    and $07     ; A is now 0-7
+    tax
+    inx         ; X is now 1-8
+    lda #$01
+L1: dex
+    beq L2
+    asl
+    bra L1  
+L2: pha         ; Push bit mask to stack
+    ora tmp1    ; A is now 1 << (0-7) | enable
+    sta IRQ_DAT_ADDR
+
+
+    lda tmp2
+    add #IRQ_CMD_TYPE
+    sta IRQ_CMD_ADDR
+    lda IRQ_DAT_ADDR
+    sta tmp1
+    jsr popa    ; A is now type
+    beq bit0
+bit1:           ; set `bit` to 1
+    pla
+    ora tmp1
+    bra L3
+bit0:           ; set `bit` to 0
+    pla
+    eor #$ff
+    and tmp1
+L3: sta IRQ_DAT_ADDR
+    rts
+
+.endproc
+
+.proc _disable_irq
+    ; Decide which byte we need to modify by dividing by 32 (>> 5)
+    pha
+    lsr
+    lsr
+    lsr
+    lsr
+    lsr         ; A is now bytesel
+    add #IRQ_CMD_ENABLE
+    sta IRQ_CMD_ADDR
+    lda IRQ_DAT_ADDR
+    sta tmp1
+    pla
+    and $07     ; A is now 0-7
+    tax
+    inx         ; X is now 1-8
+    lda #$01
+L1: dex
+    beq L2
+    asl
+    bra L1  
+L2: eor #$ff    ; Invert to set enable to 0
+    and tmp1    ; a is now ~(1 << (0-7)) & enable
+    sta IRQ_DAT_ADDR
+    rts
+.endproc
+
+; This should accept irqnum later.
+; void send_eoi();
+.proc _send_eoi
+    lda #IRQ_CMD_EOI
+    sta IRQ_CMD_ADDR
+    lda #$1
+    sta IRQ_DAT_ADDR
+    rts
+.endproc
+

sw/kernel/devices/rtc.h

@@ -0,0 +1,16 @@
+#ifndef _RTC_H
+#define _RTC_H
+
+#include <stdint.h>
+
+#define RTC_CMD_ADDR    0xeffe
+#define RTC_DAT_ADDR    0xefff
+
+/* initialize RTC with default values */
+void init_rtc(void);
+
+/* handle RTC interrupts */
+void handle_rtc(void);
+
+
+#endif

sw/kernel/devices/rtc.s

@@ -0,0 +1,78 @@
+.MACPACK generic
+
+.importzp tmp1
+
+.export _init_rtc
+.export _handle_rtc
+
+RTC_CMD = $effe
+RTC_DAT = $efff
+
+RTC_THRESHOLD       = $00
+RTC_INCREMENT       = $10
+RTC_IRQ_THRESHOLD   = $20
+RTC_OUTPUT          = $30
+RTC_CONTROL         = $30
+
+; void init_rtc(void);
+; Initialize rtc and generate 50ms interrupts
+.proc _init_rtc
+    lda #RTC_INCREMENT+0    ; Set increment to 1
+    sta RTC_CMD
+    lda #$01
+    sta RTC_DAT
+    lda #RTC_INCREMENT+1
+    sta RTC_CMD
+    lda #$00
+    sta RTC_DAT
+    lda #RTC_INCREMENT+2
+    sta RTC_CMD
+    lda #$00
+    sta RTC_DAT
+    lda #RTC_INCREMENT+3
+    sta RTC_CMD
+    lda #$00
+    sta RTC_DAT
+
+    lda #RTC_THRESHOLD+0    ; Set threshold to 4000 ($fa0)
+    sta RTC_CMD
+    lda #$a0
+    sta RTC_DAT
+    lda #RTC_THRESHOLD+1
+    sta RTC_CMD
+    lda #$0f
+    sta RTC_DAT
+    lda #RTC_THRESHOLD+2
+    sta RTC_CMD
+    lda #$00
+    sta RTC_DAT
+    lda #RTC_THRESHOLD+3
+    sta RTC_CMD
+    lda #$00
+    sta RTC_DAT
+
+    lda #RTC_THRESHOLD+0    ; Set irq threshold to 50 ($32)
+    sta RTC_CMD
+    lda #$32
+    sta RTC_DAT
+    lda #RTC_THRESHOLD+1
+    sta RTC_CMD
+    lda #$00
+    sta RTC_DAT
+    lda #RTC_THRESHOLD+2
+    sta RTC_CMD
+    lda #$00
+    sta RTC_DAT
+    lda #RTC_THRESHOLD+3
+    sta RTC_CMD
+    lda #$00
+    sta RTC_DAT
+    rts
+
+.endproc
+
+
+.proc _handle_rtc
+    nop
+    rti
+.endproc

sw/kernel/kernel.c

@@ -1,25 +1,27 @@
 #include <conio.h>
-
+#include "devices/interrupt_controller.h"
-char* longstring = \
+#include "devices/rtc.h"
-"This is a very long string that is meant to test the loader.\
- We can only load one cluster so far, which means 8 sectors of\
- 512bytes, or a total of 4k. If there was any more data than this,\
- then we would have to traverse the fat to find the next cluster number.\
- This may not be that difficult, but the file will need to be large\
- enough to actually stretch that far. The kernel will probably be\
- that big in the future, but for now when it doesnt really do anything\
- then it can't really be tested.";
 
 
 int main() {
-    char* string = "this is a shorter string";
-    int val = 42;
-    cputs("Kernel\n");
-    cprintf("Kernel printf\n");
-    cprintf("Val: %d\n", val);
-    cprintf("%s", string);
 
-    cprintf("Here is a long string: %s\n", longstring);
+    cputs("Kernel\n");
+
+    // cputs("Init Paging")
+    // init_paging()
+
+    // cputs("Initialize Interrupts");
+    // init_interrupts();
+
+    cputs("Initialize Interrupt Controller");
+    init_interrupt_controller();
+
+    cputs("Initialize RTC");
+    init_rtc();
+
+    // cputs("Initialize Serial");
+    // // init_serial();
+    // enable_irq(2, IRQ_EDGE);
 
     while(1);