CHKIN and CKOUT refactoring

c64/kernal/iec/chkin_iec.s

@@ -0,0 +1,30 @@
+
+//
+// IEC part of the CHKIN routine
+//
+
+
+#if CONFIG_IEC
+
+
+chkin_iec:
+
+	// Fail if the file is open for writing (secondary address 1)
+	
+	lda LAT, Y
+	cmp #$01
+	beq_far chkin_file_not_input
+
+	// Send TALK + TKSA first
+	lda FAT,Y
+	
+	jsr TALK
+	bcs_far chkinout_device_not_present
+
+	lda LAT, Y
+	jsr TKSA
+	bcs_far chkinout_device_not_present
+
+	jmp chkin_set_device
+
+#endif // CONFIG_IEC

c64/kernal/iec/ckout_iec.s

@@ -0,0 +1,30 @@
+
+//
+// IEC part of the CKOUT routine
+//
+
+
+#if CONFIG_IEC
+
+
+ckout_iec:
+
+	// Fail if the file is open for reading (secondary address 0)
+	
+	lda LAT, Y
+	beq_far ckout_file_not_output
+
+	// Send LISTEN + SECOND first
+	lda FAT,Y
+
+	jsr LISTEN
+	bcs_far chkinout_device_not_present
+
+	lda LAT, Y
+	jsr SECOND
+	bcs_far chkinout_device_not_present
+
+	jmp ckout_set_device
+
+
+#endif // CONFIG_IEC