add cx16diskio.vload_raw() to load headerless files into vram

compiler/res/prog8lib/cx16/cx16diskio.p8

@@ -37,14 +37,19 @@ cx16diskio {
     asmsub vload(str name @R0, ubyte device @Y, ubyte bank @A, uword address @R1) -> ubyte @A {
         ; -- like the basic command VLOAD "filename",device,bank,address
         ;    loads a file into Vera's video memory in the given bank:address, returns success in A
+        ;    the file has to have the usual 2 byte header (which will be skipped)
         %asm {{
-            ; -- load a file into video ram
+            clc
+internal_vload:
             phx
             pha
             tya
             tax
-            lda  #1
-            ldy  #0
+            bcc +
+            ldy  #%00000010     ; headerless load mode
+            bne  ++
++           ldy  #0             ; normal load mode
++           lda  #1
             jsr  c64.SETLFS
             lda  cx16.r0
             ldy  cx16.r0+1
@@ -71,6 +76,15 @@ cx16diskio {
         }}
     }
 
+    asmsub vload_raw(str name @R0, ubyte device @Y, ubyte bank @A, uword address @R1) -> ubyte @A {
+        ; -- like the basic command BVLOAD "filename",device,bank,address
+        ;    loads a file into Vera's video memory in the given bank:address, returns success in A
+        ;    the file is read fully including the first two bytes.
+        %asm {{
+            sec
+            jmp  vload.internal_vload
+        }}
+    }
 
     ; replacement function that makes use of fast block read capability of the X16
     ; use this in place of regular diskio.f_read()

docs/source/libraries.rst

@@ -365,6 +365,7 @@ cx16diskio  (cx16 only)
 -----------------------
 Available for the Cx16 target. Contains extensions to the load and load_raw routines from the regular
 diskio module, to deal with loading of potentially large files in to banked ram (HiRam).
+Routines to directly load data into video ram are also present (vload and vload_raw).
 Also contains a helper function to calculate the file size of a loaded file (although that is truncated
 to 16 bits, 64Kb)
 

docs/source/todo.rst

@@ -4,7 +4,6 @@ TODO
 For next release
 ^^^^^^^^^^^^^^^^
 - ir: asmsub contents remains blank in IR file
-- add cx16diskio.vload_raw() to load headerless files into vram
 - mention the syntax highlighting files in the readme and the docs, and add note to the IDEA one that it can also be used in Rider
 
 ...