From 60b5c5ba7441d8fce92f0f49c11bf92df269dee4 Mon Sep 17 00:00:00 2001
From: OBattler <oubattler@gmail.com>
Date: Sun, 4 Dec 2022 22:59:22 +0100
Subject: [PATCH] Implemented missing ALi M1543C behavior.

---
 src/chipset/ali1543.c   |  8 ++++++++
 src/include/86box/nvr.h |  1 +
 src/nvr_at.c            | 17 +++++++++++++++++
 3 files changed, 26 insertions(+)

diff --git a/src/chipset/ali1543.c b/src/chipset/ali1543.c
index e6bfbf878..150e54468 100644
--- a/src/chipset/ali1543.c
+++ b/src/chipset/ali1543.c
@@ -254,6 +254,14 @@ ali1533_write(int func, int addr, uint8_t val, void *priv)
                 dev->pci_conf[addr] = val & 0xcf;
             /* This actually enables/disables the USB *device* rather than the interface itself. */
             dev->usb_dev_enable = !(val & 0x40);
+            if (dev->type == 1) {
+                nvr_at_index_read_handler(0, 0x0070, dev->nvr);
+                nvr_at_index_read_handler(0, 0x0072, dev->nvr);
+                if (val & 0x20) {
+                    nvr_at_index_read_handler(1, 0x0070, dev->nvr);
+                    nvr_at_index_read_handler(1, 0x0072, dev->nvr);
+                }
+            }
             break;
 
         /* Hardware setting status bits, read-only (register 0x54) */
diff --git a/src/include/86box/nvr.h b/src/include/86box/nvr.h
index 47e52c95b..25f5e90ad 100644
--- a/src/include/86box/nvr.h
+++ b/src/include/86box/nvr.h
@@ -118,6 +118,7 @@ extern void nvr_time_set(struct tm *);
 extern void nvr_reg_write(uint16_t reg, uint8_t val, void *priv);
 extern void nvr_at_handler(int set, uint16_t base, nvr_t *nvr);
 extern void nvr_at_sec_handler(int set, uint16_t base, nvr_t *nvr);
+extern void nvr_at_index_read_handler(int set, uint16_t base, nvr_t *nvr);
 extern void nvr_read_addr_set(int set, nvr_t *nvr);
 extern void nvr_wp_set(int set, int h, nvr_t *nvr);
 extern void nvr_via_wp_set(int set, int reg, nvr_t *nvr);
diff --git a/src/nvr_at.c b/src/nvr_at.c
index 4b4cbb2a3..301399533 100644
--- a/src/nvr_at.c
+++ b/src/nvr_at.c
@@ -892,6 +892,23 @@ nvr_at_handler(int set, uint16_t base, nvr_t *nvr)
                nvr_read, NULL, NULL, nvr_write, NULL, NULL, nvr);
 }
 
+void
+nvr_at_index_read_handler(int set, uint16_t base, nvr_t *nvr)
+{
+    io_handler(0, base, 1,
+               nvr_read, NULL, NULL, NULL, NULL, NULL, nvr);
+    nvr_at_handler(0, base, nvr);
+
+    if (set)
+        nvr_at_handler(1, base, nvr);
+    else {
+        io_handler(set, base, 1,
+                   nvr_read, NULL, NULL, NULL, NULL, NULL, nvr);
+        io_handler(set, base + 1, 1,
+                   nvr_read, NULL, NULL, nvr_write, NULL, NULL, nvr);
+    }
+}
+
 void
 nvr_at_sec_handler(int set, uint16_t base, nvr_t *nvr)
 {