From 1b0344660de2832b472b0a413c50ff7f111a9293 Mon Sep 17 00:00:00 2001
From: Javier <dev.git@javispedro.com>
Date: Sun, 30 Aug 2026 02:21:09 +0200
Subject: first steps towards (optional) serial mouse support

---
 dlog.h | 41 +++++++++++++++++++++++++++++++++++------
 1 file changed, 35 insertions(+), 6 deletions(-)

(limited to 'dlog.h')

diff --git a/dlog.h b/dlog.h
index 112254e..2878ac9 100644
--- a/dlog.h
+++ b/dlog.h
@@ -29,14 +29,18 @@
 /** If 0, these routines become nops */
 #define ENABLE_DLOG 0
 /** 1 means target serial port, 0 means target IO port. */
-#define DLOG_TARGET_SERIAL 0
-/** IO port to target.
+#define DLOG_TARGET DLOG_TARGET_IOPORT
+/** When using DLOG_TARGET_IOPORT, which IO port to target.
  *  VirtualBox uses 0x504, Bochs, DOSBox and descendants use 0xE9.
- *  When using DLOG_TARGET_SERIAL, use desired UART IO base port. (e.g. COM1 = 0x3F8). */
+ *  When using DLOG_TARGET_SERIAL, the desired UART IO base port. (e.g. COM1 = 0x3F8). */
 #define DLOG_TARGET_PORT 0x504
 
 // End of customizable defines
 
+#define DLOG_TARGET_BIOSTTY 1
+#define DLOG_TARGET_SERIAL 2
+#define DLOG_TARGET_IOPORT 3
+
 #if ENABLE_DLOG
 
 /** Initializes the debug log port. */
@@ -45,7 +49,22 @@ static void dlog_init();
 /** Logs a single character to the debug message IO port. */
 static inline void dputc(char c);
 
-#if DLOG_TARGET_SERIAL
+#if DLOG_TARGET == DLOG_TARGET_BIOSTTY
+
+static inline void dlog_init()
+{
+	// No initialization required
+}
+
+static inline void dputc(char c);
+#pragma aux dputc = \
+			"mov ah, 0x0E" \
+			"xor bx, bx" \
+			"int 0x10" \
+			__parm [AL] \
+			__modify __exact [AH AL BH BL];
+
+#elif DLOG_TARGET == DLOG_TARGET_SERIAL
 
 static void dlog_init()
 {
@@ -65,7 +84,7 @@ static inline void dputc(char c)
 	outp(DLOG_TARGET_PORT, c);
 }
 
-#else /* DLOG_TARGET_SERIAL */
+#elif DLOG_TARGET == DLOG_TARGET_IOPORT
 
 static inline void dlog_init()
 {
@@ -77,7 +96,7 @@ static inline void dputc(char c)
 	outp(DLOG_TARGET_PORT, c);
 }
 
-#endif /* DLOG_TARGET_SERIAL */
+#endif /* DLOG_TARGET */
 
 static void d_utoa(unsigned num, unsigned base)
 {
@@ -265,6 +284,16 @@ static void dprintf(const char *fmt, ...)
 					break;
 				}
 				break;
+			case 'b':
+				switch (size) {
+				case sizeof(int):
+					d_utoa(va_arg(va, int), 2);
+					break;
+				case sizeof(long):
+					d_ultoa(va_arg(va, long), 2);
+					break;
+				}
+				break;
 			case 'p':
 				if (is_far) {
 					void __far *p = va_arg(va, void __far *);
-- 
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