turbo tape can now load files up to 250 blocks

c64/kernal/tape/load_tape_turbo.s

@@ -82,6 +82,18 @@ load_tape_turbo_header_loop:
 
 load_tape_turbo_payload:
 
+	// Copy helper byte store routine to RAM, provide default memory mapping
+
+	ldx #(__tape_turbo_bytestore_size - 1)
+!:
+	lda tape_turbo_bytestore_source, x
+	sta __tape_turbo_bytestore, x
+	dex
+	bpl !-
+
+	lda CPU_R6510
+	sta __tape_turbo_bytestore_defmap
+
 	// Initial checksum value
 
 	lda #$00
@@ -96,7 +108,7 @@ load_tape_turbo_payload:
 load_tape_turbo_loop:
 
 	jsr tape_turbo_get_byte
-	sta (MEMUSS),y
+	jsr __tape_turbo_bytestore         // like 'sta (MEMUSS),y' - but under I/O
 
 	eor PRTY                           // handle checksum
 	sta PRTY

c64/kernal/tape/tape_turbo_bytestore.s

@@ -0,0 +1,40 @@
+
+//
+// Tape (turbo) helper routine - storing byte uder I/O
+//
+
+// This helper routine is meant to be copiet to the start of CPU stack.
+// Original ROM tape loading routines uses this area to store information
+// about bytes that did not read properly for the first time
+// (see Mapping the C64, page 47); this mechanism is useless for turbo tape,
+// but it means we can safely use this area for our purposes
+
+
+#if CONFIG_TAPE_TURBO
+
+
+.label __tape_turbo_bytestore         = STACK
+.label __tape_turbo_bytestore_defmap  = __tape_turbo_bytestore + 7
+.label __tape_turbo_bytestore_size    = __tape_turbo_bytestore_source_end - tape_turbo_bytestore_source
+
+
+tape_turbo_bytestore_source:
+
+	// Set all memory as RAM, tape motor ON
+	ldx #$00
+	stx CPU_R6510
+
+	// Store byte in memory
+	sta (MEMUSS), y
+
+	// Restore default memory layout
+	ldx #$00                           // value will be determined later, offset from start: 7 bytes
+	stx CPU_R6510
+
+	// Go back
+	rts
+
+__tape_turbo_bytestore_source_end:
+
+
+#endif // CONFIG_TAPE_TURBO