tape normal block reading added

c64/kernal/iostack/load_save_common.s

@@ -85,6 +85,10 @@ lvs_setup_MEMUSS:
 	sta MEMUSS+1
 	rts
 
+#endif
+
+#if CONFIG_TAPE_TURBO || CONFIG_IEC
+
 lvs_advance_MEMUSS_check_EAL:
 
 	// Advance pointer
@@ -95,7 +99,15 @@ lvs_advance_MEMUSS_check_EAL:
 !:
 #else
 	inw MEMUSS+0
+
 #endif
+
+	// FALLTROUGH
+
+#if CONFIG_TAPE_NORMAL || CONFIG_TAPE_TURBO || CONFIG_IEC
+
+lvs_check_EAL:
+
 	lda MEMUSS+1
 	cmp EAL+1
 	bne !+

c64/kernal/tape/load_tape_normal.s

@@ -117,18 +117,24 @@ load_tape_normal_header_loop:
 
 load_tape_normal_payload:
 
-	jsr tape_normal_pilot
-	ldy #$09
-	jsr tape_normal_sync
+	// Retrieve block
 
+	jsr tape_normal_get_block // XXX handle errors
 
+	// Advance MEMUSS (see Mapping the C64, page 36), check if end
 
-
-	// XXX replace this placeholder with a real routine
+	tya
+	clc
+	adc MEMUSS+0
+	sta MEMUSS+0
+	bcc !+
+	inc MEMUSS+1
 !:
-	jsr tape_normal_get_marker
-	jsr tape_normal_get_byte
-	jmp !-
+
+	jsr lvs_check_EAL
+	bne load_tape_normal_payload
+
+	jmp tape_load_success
 
 
 #endif

c64/kernal/tape/tape_normal_get_bit.s

@@ -1,6 +1,6 @@
 
 //
-// Tape (turbo) helper routine - bit reading
+// Tape (normal) helper routine - bit reading
 //
 // Returns bit in Zero flag, Carry set means error, on 0 bit .A is 0 too
 //

c64/kernal/tape/tape_normal_get_block.s

@@ -0,0 +1,74 @@
+
+//
+// Tape (normal) helper routine - block reading
+//
+// Stores data starting from MEMUSS, Carry set means error, on 0 bit .A is 0 too
+//
+
+
+// XXX does not detect block end - find out why
+// XXX improve error handling - do not ignore second copy, handle damaged checksum byte, handle damaged sync part
+
+
+tape_normal_get_block:
+
+	// Read the pilot and sync of the block
+
+	jsr tape_normal_pilot
+	ldy #$89
+	jsr tape_normal_sync // XXX handle result
+	
+	// Initialize byte counter and block checksum (RIPRTY, see http://sta.c64.org/cbm64mem.html)
+	ldy #$00
+	sty RIPRTY
+
+tape_normal_get_block_loop:
+
+	jsr tape_normal_get_marker
+	bcs tape_normal_get_block_checksum // end of data for the block
+	jsr tape_normal_get_byte
+
+	bcs tape_normal_get_block_done     // error reading byte - fatal for now
+
+	// Store byte, calculate checksum
+	sta (MEMUSS), y
+	eor RIPRTY
+	sta RIPRTY
+	
+	iny
+	bne tape_normal_get_block_loop
+
+	// FALLTROUGH - if we are here, it means the block is too long
+	
+tape_normal_get_block_done_fail:
+	
+	sec
+	rts
+
+tape_normal_get_block_checksum:
+.break
+	jsr tape_normal_get_byte
+	bcs tape_normal_get_block_done     // cannot get block checksum - fatal for now
+
+	eor RIPRTY
+	cmp #$01
+	bcs tape_normal_get_block_done     // checksum error - fatal for now
+
+	// Read trailing pulses
+	
+	jsr tape_normal_sync // XXX handle result
+	
+	// Read the pilot and sync of the backup block
+
+	jsr tape_normal_pilot
+	ldy #$09
+	jsr tape_normal_sync // XXX handle result
+	
+	// For now we ignore the backup block
+	clc
+
+	// FALLTROUGH
+
+tape_normal_get_block_done:
+
+	rts