From 0cafc8defb2a30bff5f0eb6f6f8a12e1a25e2cd6 Mon Sep 17 00:00:00 2001
From: FeralChild64 <you@example.com>
Date: Thu, 26 Dec 2019 16:24:13 +0100
Subject: [PATCH] IEC code size optimizations

---
 c64/kernal/iec/iec_wait60us.s         |  8 ++++++--
 c64/kernal/iec/load_iec.s             |  2 +-
 c64/kernal/iec_fast/iec_fast_common.s | 22 ++++++++++++++++++++++
 c64/kernal/iec_fast/load_dolphindos.s | 14 +++-----------
 c64/kernal/iec_fast/load_jiffydos.s   |  9 ++-------
 5 files changed, 34 insertions(+), 21 deletions(-)
 create mode 100644 c64/kernal/iec_fast/iec_fast_common.s

diff --git a/c64/kernal/iec/iec_wait60us.s b/c64/kernal/iec/iec_wait60us.s
index f748ea28..5673d528 100644
--- a/c64/kernal/iec/iec_wait60us.s
+++ b/c64/kernal/iec/iec_wait60us.s
@@ -1,4 +1,8 @@
 
+//
+// Note: damages .X
+//
+
 
 #if CONFIG_IEC
 
@@ -14,8 +18,8 @@ iec_wait60us:
 
 	// Waste cycles in a loop
 
-	ldy #$0A   // 2 cycles
-!:	dey        // 2 cycles * 10
+	ldx #$0A   // 2 cycles
+!:	dex        // 2 cycles * 10
 	bpl !-     // 3 cycles * 9  + 2 cycles
 	rts        // 6 cycles
 
diff --git a/c64/kernal/iec/load_iec.s b/c64/kernal/iec/load_iec.s
index cf5e5995..ccbff761 100644
--- a/c64/kernal/iec/load_iec.s
+++ b/c64/kernal/iec/load_iec.s
@@ -93,7 +93,7 @@ load_iec:
 	// Display start address
 	jsr lvs_display_loading_verifying
 
-#if CONFIG_IEC_JIFFYDOS && !CONFIG_MEMORY_MODEL_60K
+#if (CONFIG_IEC_JIFFYDOS || CONFIG_IEC_DOLPHINDOS) && !CONFIG_MEMORY_MODEL_60K
 
 	// If feasible, use JiffyDOS optimized LOAD loop
 
diff --git a/c64/kernal/iec_fast/iec_fast_common.s b/c64/kernal/iec_fast/iec_fast_common.s
new file mode 100644
index 00000000..9b8cf89d
--- /dev/null
+++ b/c64/kernal/iec_fast/iec_fast_common.s
@@ -0,0 +1,22 @@
+
+//
+// Common routines for multiple IEC fact protocols
+//
+
+
+#if (CONFIG_IEC_JIFFYDOS || CONFIG_IEC_DOLPHINDOS) && !CONFIG_MEMORY_MODEL_60K
+
+
+iec_update_EAL_by_Y:
+
+	tya
+	sec
+	adc EAL+0
+	sta EAL+0
+	bcc !+
+	inc EAL+1
+!:
+	rts
+
+
+#endif
diff --git a/c64/kernal/iec_fast/load_dolphindos.s b/c64/kernal/iec_fast/load_dolphindos.s
index 27258a14..eb7a18af 100644
--- a/c64/kernal/iec_fast/load_dolphindos.s
+++ b/c64/kernal/iec_fast/load_dolphindos.s
@@ -39,10 +39,8 @@ load_dolphindos_loop:
 	lda CIA2_PRA
 	bpl !-
 
-	// Check if EOI - routine can damage .Y, so store it in safe place
-	sty TBTCNT
+	// Check if EOI - routine can damage .X, but this is safe
 	jsr iec_rx_check_eoi
-	ldy TBTCNT
 
 	// Retrieve and store byte
 	lda CIA2_PRB
@@ -62,14 +60,8 @@ load_dolphindos_loop:
 
 load_dolphindos_end:
 
-	// Update EAL - XXX deduplicate with JiffyDOS counterpart
-	tya
-	sec
-	adc EAL+0
-	sta EAL+0
-	bcc !+
-	inc EAL+1
-!:
+	// Update EAL
+	jsr iec_update_EAL_by_Y
 
 	// End of load loop
 	jmp load_iec_loop_end
diff --git a/c64/kernal/iec_fast/load_jiffydos.s b/c64/kernal/iec_fast/load_jiffydos.s
index acb0c7e5..923e7dbc 100644
--- a/c64/kernal/iec_fast/load_jiffydos.s
+++ b/c64/kernal/iec_fast/load_jiffydos.s
@@ -132,13 +132,8 @@ load_jiffydos_end:
 	tax
 
 	// Update EAL
-	tya
-	sec
-	adc EAL+0
-	sta EAL+0
-	bcc !+
-	inc EAL+1
-!:
+	jsr iec_update_EAL_by_Y
+
 	// Indicate that no byte waits in output buffer
 	lda #$00
 	sta C3PO