added cx16diskio with load() and load_raw() that are HIMEM bank-aware

compiler/res/prog8lib/cx16/cx16diskio.p8

@@ -0,0 +1,38 @@
+; Cx16 specific disk drive I/O routines.
+;
+; Written by Irmen de Jong (irmen@razorvine.net) - license: GNU GPL 3.0
+
+%import diskio
+
+cx16diskio {
+
+    ; Use kernal LOAD routine to load the given program file in memory.
+    ; This mimimics Basic's  LOAD "filename",drive  /  LOAD "filename",drive,1
+    ; If you don't give an address_override, the location in memory is taken from the 2-byte file header.
+    ; If you specify a custom address_override, the first 2 bytes in the file are ignored
+    ; and the rest is loaded at the given location in memory.
+    ; Returns the number of bytes loaded (truncated to 16 bits, if the file is larger than 64 Kb,
+    ; you'll have to compensate yourself by checking the ram banks).
+    sub load(ubyte drivenumber, uword filenameptr, ubyte bank, uword address_override) -> uword {
+        cx16.rambank(bank)
+        uword size = diskio.load(drivenumber, filenameptr, address_override)
+        if size
+            return size + $2000 * (cx16.getrambank() - bank)
+        return 0
+    }
+
+    ; Use kernal LOAD routine to load the given file in memory.
+    ; INCLUDING the first 2 bytes in the file: no program header is assumed in the file.
+    ; This is different from Basic's LOAD instruction which always skips the first two bytes.
+    ; The load address is mandatory. Returns the number of bytes loaded.
+    ; Returns the number of bytes loaded (truncated to 16 bits, if the file is larger than 64 Kb,
+    ; you'll have to compensate yourself by checking the ram banks).
+    sub load_raw(ubyte drivenumber, uword filenameptr, ubyte bank, uword address) -> uword {
+        cx16.rambank(bank)
+        uword size = diskio.load_raw(drivenumber, filenameptr, address)
+        if size
+            return size + $2000 * (cx16.getrambank() - bank)
+        return 0
+    }
+
+}

compiler/res/prog8lib/diskio.p8

@@ -440,7 +440,9 @@ io_error:
     ; and the rest is loaded at the given location in memory.
     ; Returns the number of bytes loaded.
     ; NOTE: when the load is larger than 64Kb and/or spans multiple RAM banks
-    ;       (which is possible on the Commander X16), the returned size is not correct.
+    ;       (which is possible on the Commander X16), the returned size is not correct,
+    ;       because it doesn't take the number of ram banks into account.
+    ;       Consider using cx16diskio.load() instead.
     sub load(ubyte drivenumber, uword filenameptr, uword address_override) -> uword {
         c64.SETNAM(string.length(filenameptr), filenameptr)
         ubyte secondary = 1
@@ -474,16 +476,21 @@ io_error:
     ; This is different from Basic's LOAD instruction which always skips the first two bytes.
     ; The load address is mandatory. Returns the number of bytes loaded.
     ; NOTE: when the load is larger than 64Kb and/or spans multiple RAM banks
-    ;       (which is possible on the Commander X16), the returned size is not correct.
+    ;       (which is possible on the Commander X16), the returned size is not correct,
+    ;       because it doesn't take the number of ram banks into account.
+    ;       Consider using cx16diskio.load_raw() instead.
     sub load_raw(ubyte drivenumber, uword filenameptr, uword address) -> uword {
         if not f_open(drivenumber, filenameptr)
             return 0
-        uword read = f_read(address, 2)
+        uword size = f_read(address, 2)
         f_close()
-        if read!=2
+        if size!=2
             return 0
         address += 2
-        return 2+load(drivenumber, filenameptr, address)
+        size = load(drivenumber, filenameptr, address)
+        if size
+            return size+2
+        return 0
     }
 
     sub delete(ubyte drivenumber, uword filenameptr) {