init

2026-09-19 20:21:47 +02:00
commit 0798933b05
62 changed files with 7658 additions and 0 deletions
@@ -0,0 +1,20 @@
+; ECHO -- copy each day's uplink into the downlink buffer.
+;
+        .equ    RX      0               ; uplink buffer
+        .equ    TX      1024            ; downlink buffer
+        .equ    P_UPNEW 0x70            ; uplink-arrived flag / acknowledge
+        .equ    P_UPLEN 0x71            ; uplink length in bytes
+
+wait:   in      r1, P_UPNEW
+        ldi     r2, 0
+        beq     r1, r2, sleep           ; nothing new today
+        in      r4, P_UPLEN
+        ldi     r5, 0                   ; r5 = byte index
+copy:   bge     r5, r4, done
+        ldb     r6, [r5+RX]
+        stb     r6, [r5+TX]
+        addi    r5, 1
+        jmp     copy
+done:   out     P_UPNEW, r1             ; acknowledge
+sleep:  yield
+        jmp     wait