Add timer and test program

hw/efinix_fpga/test_programs/timer.s

@@ -0,0 +1,38 @@
+.code
+
+LEDS = $efff
+TIMER_BASE = $eff8
+TIMER_DIVISOR = 5
+
+TIMER_OLD = $10
+
+main:
+    lda #$ff
+    sta TIMER_BASE+TIMER_DIVISOR
+    lda TIMER_BASE
+    sta TIMER_OLD
+    stz LEDS
+
+
+; load the new value of the timer in a
+; subtract the old value of the timer
+; if the result is greater than 30, then do something
+
+loop:
+    lda TIMER_BASE
+    tax
+    sec
+    sbc TIMER_OLD
+    sec
+    sbc #$20
+    bcc loop
+
+    stx TIMER_OLD
+    inc LEDS
+    bra loop
+    
+.segment "VECTORS"
+
+.addr main
+.addr main
+.addr main