Memory controller implemented.

2026-08-15 20:43:53 -04:00
parent c4b2c27a2d
commit 04dfcd707b
32 changed files with 1842 additions and 21 deletions
@@ -0,0 +1,40 @@
+; Running off the end of a bank.
+;
+; Bank 2 is the bank table: 256 banks at eight bytes each, so 2048 bytes exactly. The
+; last byte is at 0x07FF and there is nothing at 0x0800. A bank knowing how big it is
+; means the difference shows up as a fault at the instruction that overran, instead of
+; quietly reading whatever happened to be next in the emulator's memory.
+;
+; Nothing is installed for BankFault here, so the machine stops.
+;
+; Correct output is:
+;   O                the last byte of the bank was read without complaint
+;   a fault naming port 233, which is the controller's Data port, and a non zero exit.
+
+#Program
+
+start:
+  INIA 0d2
+  OUTA 0xE0         ; SourceBank = 2
+  INIA 0x07
+  OUTA 0xE1
+  INIA 0xFF
+  OUTA 0xE2         ; 0x07FF, the last byte there is
+
+  INA 0xE9          ; Fine.
+  INIA 0d79         ; 'O'
+  OUTA 0x00
+  INIA 0x0A
+  OUTA 0x00
+
+  INIA 0x08
+  OUTA 0xE1
+  RSTA
+  OUTA 0xE2         ; 0x0800, one past the end
+
+  INA 0xE9          ; Refused: BankFault.
+
+  ; Never reached.
+  INIA 0d88         ; 'X'
+  OUTA 0x00
+  HALT