From 5fa1c1715447eac9d685c16ecabdc2407eb60a1b Mon Sep 17 00:00:00 2001
From: OBattler <oubattler@gmail.com>
Date: Mon, 1 Sep 2025 22:13:37 +0200
Subject: [PATCH] LPT: Impelement ECP FIFO test mode, fixes printing in ECP
 mode on the ASUS P/I-P55T2P4.

---
 src/device/lpt.c | 35 ++++++++++++++++++++++-------------
 1 file changed, 22 insertions(+), 13 deletions(-)

diff --git a/src/device/lpt.c b/src/device/lpt.c
index 268e4200e..f7cc6eda0 100644
--- a/src/device/lpt.c
+++ b/src/device/lpt.c
@@ -236,7 +236,7 @@ lpt_fifo_out_callback(void *priv)
 {
     lpt_t *dev = (lpt_t *) priv;
 
-    switch (dev->state) {
+    if ((dev->ecr & 0xe0) != 0xc0)  switch (dev->state) {
         default:
             break;
 
@@ -281,7 +281,7 @@ lpt_fifo_out_callback(void *priv)
                 }
             }
 
-            if (dev->ecr & 0x08) {
+            if (((dev->ecr & 0xe0) != 0xc0) && (dev->ecr & 0x08)) {
                 if (fifo_get_empty(dev->fifo)) {
                     if (dev->dma_stat) {
                         /* Now actually set the external flag. */
@@ -319,7 +319,8 @@ lpt_write(const uint16_t port, const uint8_t val, void *priv)
     switch (port & mask) {
         case 0x0000:
             if (dev->ecp) {
-                if (((dev->ecr & 0xe0) == 0x40) || ((dev->ecr & 0xe0) == 0x60))
+                if (((dev->ecr & 0xe0) == 0x40) || ((dev->ecr & 0xe0) == 0x60) ||
+                    ((dev->ecr & 0xe0) == 0xc0))
                     /* AFIFO */
                     lpt_write_fifo(dev, val, 0x00);
                 else if (!(dev->ecr & 0xc0) && (!(dev->ecr & 0x20) || !(lpt_get_ctrl_raw(dev) & 0x20)) &&
@@ -398,18 +399,13 @@ lpt_write(const uint16_t port, const uint8_t val, void *priv)
             switch (dev->ecr >> 5) {
                 default:
                     break;
-                case 2:
+                case 2: case 6:
                     lpt_write_fifo(dev, val, 0x01);
                     break;
                 case 3:
                     if (!(lpt_get_ctrl_raw(dev) & 0x20))
                         lpt_write_fifo(dev, val, 0x01);
                     break;
-                case 6:
-                    /* TFIFO */
-                    if (!fifo_get_full(dev->fifo))
-                        fifo_write_evt(val, dev->fifo);
-                    break;
             }
             break;
 
@@ -424,7 +420,8 @@ lpt_write(const uint16_t port, const uint8_t val, void *priv)
                         timer_set_delay_u64(&dev->fifo_out_timer, (uint64_t) ((1000000.0 / 2500000.0) * (double) TIMER_USEC));
                 } else {
                     dev->state = LPT_STATE_WRITE_FIFO;
-                    if (((dev->ecr & 0xe0) == 0x40) || (lpt_get_ctrl_raw(dev) & 0x20))
+                    if (((dev->ecr & 0xe0) == 0x40) || ((dev->ecr & 0xe0) == 0xc0) ||
+                        (lpt_get_ctrl_raw(dev) & 0x20))
                         dev->fifo_stat = fifo_get_ready(dev->fifo) ? 0x04 : 0x00;
                     else
                         dev->fifo_stat = fifo_get_ready(dev->fifo) ? 0x00 : 0x04;
@@ -463,7 +460,8 @@ lpt_fifo_d_ready_evt(void *priv)
     lpt_t *dev = (lpt_t *) priv;
 
     if (!(dev->ecr & 0x08)) {
-        if (((dev->ecr & 0xe0) == 0x40) || (lpt_get_ctrl_raw(dev) & 0x20))
+        if (((dev->ecr & 0xe0) == 0xc0) || ((dev->ecr & 0xe0) == 0x40) ||
+            (lpt_get_ctrl_raw(dev) & 0x20))
             dev->fifo_stat = fifo_get_ready(dev->fifo) ? 0x04 : 0x00;
         else
             dev->fifo_stat = fifo_get_ready(dev->fifo) ? 0x00 : 0x04;
@@ -482,11 +480,13 @@ lpt_write_to_fifo(void *priv, const uint8_t val)
             dev->dat = val;
         else if (((dev->ecr & 0xe0) == 0x40) && !fifo_get_full(dev->fifo))
             fifo_write_evt_tagged(0x01, val, dev->fifo);
+        else if (((dev->ecr & 0xe0) == 0xc0) && !fifo_get_full(dev->fifo))
+            fifo_write_evt_tagged(0x01, val, dev->fifo);
         else if (((dev->ecr & 0xe0) == 0x60) && (lpt_get_ctrl_raw(dev) & 0x20) &&
             !fifo_get_full(dev->fifo))
             fifo_write_evt_tagged(0x01, val, dev->fifo);
 
-        if (((dev->ecr & 0x0c) == 0x08) && (dev->dma != 0xff)) {
+        if (((dev->ecr & 0xe0) != 0xc0) && ((dev->ecr & 0x0c) == 0x08) && (dev->dma != 0xff)) {
             const int ret = dma_channel_write(dev->dma, val);
 
             if (ret & DMA_OVER)
@@ -565,7 +565,16 @@ lpt_read(const uint16_t port, void *priv)
     switch (port & mask) {
         case 0x0000:
             if (dev->ecp) {
-                if (!(dev->ecr & 0xc0))
+                if (dev->ecr & 0xc0) {
+                    if (((dev->ecr & 0xe0) == 0xc0) && !fifo_get_empty(dev->fifo)) {
+                        uint8_t tag = 0x00;
+                        ret = fifo_read_evt_tagged(&tag, dev->fifo);
+                    } else if (((dev->ecr & 0xe0) == 0x60) && !(lpt_get_ctrl_raw(dev) & 0x20) &&
+                               !fifo_get_empty(dev->fifo)) {
+                        uint8_t tag = 0x00;
+                        ret = fifo_read_evt_tagged(&tag, dev->fifo);
+                    }
+                } else
                     ret = dev->dat;
             } else {
                 /* DTR */