From 506d9d5c4faacf31eaae9b3c92ddc55f8e446c8b Mon Sep 17 00:00:00 2001
From: FeralChild64 <you@example.com>
Date: Sun, 1 Dec 2019 16:29:00 +0100
Subject: [PATCH] compatibility fix for EOI handling in IEC code

---
 c64/kernal/iec/acptr.s       | 10 ++++++++--
 c64/kernal/iec/chrin_iec.s   |  2 +-
 c64/kernal/iec/iec_rx_byte.s | 12 ++----------
 c64/kernal/iec/load_iec.s    | 36 ++++++++++++++++++++++--------------
 4 files changed, 33 insertions(+), 27 deletions(-)

diff --git a/c64/kernal/iec/acptr.s b/c64/kernal/iec/acptr.s
index f31bfc74..e5e818e7 100644
--- a/c64/kernal/iec/acptr.s
+++ b/c64/kernal/iec/acptr.s
@@ -11,8 +11,14 @@
 
 ACPTR:
 
-	jsr kernalstatus_reset
-	
+	lda IOSTATUS
+	beq !+
+
+	lda #$0D                           // tested on real ROMs
+	clc
+	rts
+!:
+
 #if CONFIG_IEC
 #if CONFIG_IEC_JIFFYDOS
 	jmp iec_rx_dispatch
diff --git a/c64/kernal/iec/chrin_iec.s b/c64/kernal/iec/chrin_iec.s
index f293fa0c..93ad7afc 100644
--- a/c64/kernal/iec/chrin_iec.s
+++ b/c64/kernal/iec/chrin_iec.s
@@ -7,4 +7,4 @@
 chrin_iec:
 
 	// XXX is this really all?
-	jmp JACPTR // carry will be set accordingly
+	jmp JACPTR
diff --git a/c64/kernal/iec/iec_rx_byte.s b/c64/kernal/iec/iec_rx_byte.s
index 36f00f78..ac6f807a 100644
--- a/c64/kernal/iec/iec_rx_byte.s
+++ b/c64/kernal/iec/iec_rx_byte.s
@@ -111,16 +111,8 @@ iec_rx_clk_wait2:
 	// Timeout
 	jsr kernalstatus_EOI
 	pla
-	
-	// Restore registers
-	pla
-	tay
-	pla
-	tax
-    
-	sec // XXX confirm that sec is really a way to report timeout here
-	cli
-	rts
+
+	jmp iec_rx_end
 !:
 	// More bits?
 	dex
diff --git a/c64/kernal/iec/load_iec.s b/c64/kernal/iec/load_iec.s
index 23f647b8..4175ab41 100644
--- a/c64/kernal/iec/load_iec.s
+++ b/c64/kernal/iec/load_iec.s
@@ -24,8 +24,6 @@ load_break_error:
 	jsr iec_close_load
 	jmp kernalerror_ROUTINE_TERMINATED 
 
-load_save_no_file_name:
-
 
 load_iec:
 
@@ -71,19 +69,10 @@ load_iec:
 
 	// Get load address
 
-#if CONFIG_IEC_JIFFYDOS
-	jsr iec_rx_dispatch
-#else // no turbo supported
-	jsr iec_rx_byte
-#endif
-	bcs load_iec_file_not_found
+	jsr load_iec_get_addr_byte
 	sta EAL+0
-#if CONFIG_IEC_JIFFYDOS
-	jsr iec_rx_dispatch
-#else // no turbo supported
-	jsr iec_rx_byte
-#endif
-	bcs load_iec_file_not_found
+
+	jsr load_iec_get_addr_byte
 	sta EAL+1
 
 	// If secondary address is 0, override EAL with STAL
@@ -143,4 +132,23 @@ iec_load_loop:
 	jmp lvs_return_last_address
 
 
+load_iec_get_addr_byte:
+
+#if CONFIG_IEC_JIFFYDOS
+	jsr iec_rx_dispatch
+#else // no turbo supported
+	jsr iec_rx_byte
+#endif
+
+	bcs !+
+	lda IOSTATUS
+	and #K_STS_EOI
+	bne !+
+	rts
+!:
+	pla
+	pla
+	jmp load_iec_file_not_found
+
+
 #endif // CONFIG_IEC