Add quick uart irq test

sw/test_code/uart_irq_test/Makefile

@@ -0,0 +1,42 @@
+CC=../../cc65/bin/cl65
+LD=../../cc65/bin/cl65
+CFLAGS=-T -t none -I. --cpu "65C02"
+LDFLAGS=-C link.ld -m $(NAME).map
+
+NAME=uart_irq_test
+
+DEVICES=$(REPO_TOP)/sw/kernel/devices
+
+BIN=$(NAME).bin
+HEX=$(NAME).hex
+
+LISTS=lists
+
+SRCS=$(wildcard *.s) $(wildcard *.c)
+SRCS+=$(DEVICES)/interrupt_controller.s
+SRCS+=$(wildcard **/*.s) $(wildcard **/*.c)
+OBJS+=$(patsubst %.s,%.o,$(filter %s,$(SRCS)))
+OBJS+=$(patsubst %.c,%.o,$(filter %c,$(SRCS)))
+
+# Make sure the kernel linked to correct address, no relocation!
+all: $(HEX)
+
+$(HEX): $(BIN)
+	objcopy --input-target=binary --output-target=verilog $(BIN) $(HEX)
+
+$(BIN): $(OBJS)
+	$(CC) $(CFLAGS) $(LDFLAGS) $(OBJS) -o $@
+
+%.o: %.c $(LISTS)
+	$(CC) $(CFLAGS) -l $(LISTS)/$<.list -c $< -o $@
+
+%.o: %.s $(LISTS)
+	$(CC) $(CFLAGS) -l $(LISTS)/$<.list -c $< -o $@
+
+$(LISTS):
+	mkdir -p $(addprefix $(LISTS)/,$(sort $(dir $(SRCS))))
+
+.PHONY: clean
+clean:
+	rm -rf $(OBJS) $(BIN) $(HEX) $(LISTS) $(NAME).map
+

sw/test_code/uart_irq_test/link.ld

@@ -0,0 +1,35 @@
+MEMORY
+{
+  ZP:  start = $0,    size = $100,  type = rw, define = yes;
+  SDRAM: start = $9200, size = $4d00, type = rw, define = yes;
+  ROM: start = $F000, size = $1000, file = %O;
+}
+
+SEGMENTS {
+    ZEROPAGE: load = ZP,  type = zp,  define   = yes;
+    DATA:     load = ROM, type = rw,  define   = yes, run = SDRAM;
+    BSS:      load = SDRAM, type = bss, define   = yes;
+    HEAP:     load = SDRAM, type = bss, optional = yes;
+    STARTUP:  load = ROM, type = ro;
+    ONCE:     load = ROM, type = ro,  optional = yes;
+    CODE:     load = ROM, type = ro;
+    RODATA:   load = ROM, type = ro;
+    VECTORS:  load = ROM, type = ro,  start    = $FFFA;
+}
+
+FEATURES {
+    CONDES:    segment = STARTUP,
+               type    = constructor,
+               label   = __CONSTRUCTOR_TABLE__,
+               count   = __CONSTRUCTOR_COUNT__;
+    CONDES:    segment = STARTUP,
+               type    = destructor,
+               label   = __DESTRUCTOR_TABLE__,
+               count   = __DESTRUCTOR_COUNT__;
+}
+
+SYMBOLS {
+    # Define the stack size for the application
+    __STACKSIZE__:  value = $0200, type = weak;
+    __STACKSTART__: type = weak, value = $0800; # 2k stack
+}

sw/test_code/uart_irq_test/main.s

@@ -0,0 +1,35 @@
+.export _init, nmi_int, irq_int
+
+.autoimport
+
+.import _init_interrupt_controller
+
+.zeropage
+
+finish: .res 1
+
+.code
+
+nmi_int:
+irq_int:
+    lda #$6d
+    sta $00
+
+_init:
+    ldx #$ff
+    txs
+
+    LDA     #<(__STACKSTART__ + __STACKSIZE__)
+    STA     sp
+    LDA     #>(__STACKSTART__ + __STACKSIZE__)
+    STA     sp+1
+
+    ; enable interrupt 0
+    lda #$00
+    jsr pusha
+    lda #$1
+    jsr _enable_irq
+
+    cli
+
+@end:   bra @end

sw/test_code/uart_irq_test/vectors.s

@@ -0,0 +1,14 @@
+; ---------------------------------------------------------------------------
+; vectors.s
+; ---------------------------------------------------------------------------
+;
+; Defines the interrupt vector table.
+
+.import    _init
+.import    nmi_int, irq_int
+
+.segment  "VECTORS"
+
+.addr      nmi_int    ; NMI vector
+.addr      _init       ; Reset vector
+.addr      irq_int    ; IRQ/BRK vector