From 1589c86ebedef4a9bd6784a52a7d41fa2d5acdf9 Mon Sep 17 00:00:00 2001
From: Peter Veenstra <qbix79@users.sourceforge.net>
Date: Wed, 5 Jan 2011 19:48:18 +0000
Subject: [PATCH] Some FCB read/write refinements. Stop exiting on weird int 21
 0x33 calls. (ripsaw)

Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@3666
---
 include/dos_inc.h     |  4 ++--
 src/dos/dos.cpp       | 18 +++++++++++++-----
 src/dos/dos_files.cpp | 26 +++++++++++++-------------
 3 files changed, 28 insertions(+), 20 deletions(-)

diff --git a/include/dos_inc.h b/include/dos_inc.h
index 290d76b3..5199e506 100644
--- a/include/dos_inc.h
+++ b/include/dos_inc.h
@@ -176,8 +176,8 @@ bool DOS_FCBFindFirst(Bit16u seg,Bit16u offset);
 bool DOS_FCBFindNext(Bit16u seg,Bit16u offset);
 Bit8u DOS_FCBRead(Bit16u seg,Bit16u offset, Bit16u numBlocks);
 Bit8u DOS_FCBWrite(Bit16u seg,Bit16u offset,Bit16u numBlocks);
-Bit8u DOS_FCBRandomRead(Bit16u seg,Bit16u offset,Bit16u numRec,bool restore);
-Bit8u DOS_FCBRandomWrite(Bit16u seg,Bit16u offset,Bit16u numRec,bool restore);
+Bit8u DOS_FCBRandomRead(Bit16u seg,Bit16u offset,Bit16u * numRec,bool restore);
+Bit8u DOS_FCBRandomWrite(Bit16u seg,Bit16u offset,Bit16u * numRec,bool restore);
 bool DOS_FCBGetFileSize(Bit16u seg,Bit16u offset);
 bool DOS_FCBDeleteFile(Bit16u seg,Bit16u offset);
 bool DOS_FCBRenameFile(Bit16u seg, Bit16u offset);
diff --git a/src/dos/dos.cpp b/src/dos/dos.cpp
index fb490c27..318095b2 100644
--- a/src/dos/dos.cpp
+++ b/src/dos/dos.cpp
@@ -319,11 +319,17 @@ static Bitu DOS_21Handler(void) {
 		if (!DOS_GetAllocationInfo(reg_dl,&reg_cx,&reg_al,&reg_dx)) reg_al=0xff;
 		break;
 	case 0x21:		/* Read random record from FCB */
-		reg_al = DOS_FCBRandomRead(SegValue(ds),reg_dx,1,true);
+		{
+			Bit16u toread=1;
+			reg_al = DOS_FCBRandomRead(SegValue(ds),reg_dx,&toread,true);
+		}
 		LOG(LOG_FCB,LOG_NORMAL)("DOS:0x21 FCB-Random read used, result:al=%d",reg_al);
 		break;
 	case 0x22:		/* Write random record to FCB */
-		reg_al=DOS_FCBRandomWrite(SegValue(ds),reg_dx,1,true);
+		{
+			Bit16u towrite=1;
+			reg_al=DOS_FCBRandomWrite(SegValue(ds),reg_dx,&towrite,true);
+		}
 		LOG(LOG_FCB,LOG_NORMAL)("DOS:0x22 FCB-Random write used, result:al=%d",reg_al);
 		break;
 	case 0x23:		/* Get file size for FCB */
@@ -334,11 +340,11 @@ static Bitu DOS_21Handler(void) {
 		DOS_FCBSetRandomRecord(SegValue(ds),reg_dx);
 		break;
 	case 0x27:		/* Random block read from FCB */
-		reg_al = DOS_FCBRandomRead(SegValue(ds),reg_dx,reg_cx,false);
+		reg_al = DOS_FCBRandomRead(SegValue(ds),reg_dx,&reg_cx,false);
 		LOG(LOG_FCB,LOG_NORMAL)("DOS:0x27 FCB-Random(block) read used, result:al=%d",reg_al);
 		break;
 	case 0x28:		/* Random Block write to FCB */
-		reg_al=DOS_FCBRandomWrite(SegValue(ds),reg_dx,reg_cx,false);
+		reg_al=DOS_FCBRandomWrite(SegValue(ds),reg_dx,&reg_cx,false);
 		LOG(LOG_FCB,LOG_NORMAL)("DOS:0x28 FCB-Random(block) write used, result:al=%d",reg_al);
 		break;
 	case 0x29:		/* Parse filename into FCB */
@@ -462,7 +468,9 @@ static Bitu DOS_21Handler(void) {
 				reg_dh=0x10;								/* Dos in HMA */
 				break;
 			default:
-				E_Exit("DOS:Illegal 0x33 Call %2X",reg_al);					
+				LOG(LOG_DOSMISC,LOG_ERROR)("Weird 0x33 call %2X",reg_al);
+				reg_al =0xff;
+				break;
 		}
 		break;
 	case 0x34:		/* Get INDos Flag */
diff --git a/src/dos/dos_files.cpp b/src/dos/dos_files.cpp
index 9fe36bcb..a9c7e12b 100644
--- a/src/dos/dos_files.cpp
+++ b/src/dos/dos_files.cpp
@@ -1067,32 +1067,30 @@ Bit8u DOS_FCBIncreaseSize(Bit16u seg,Bit16u offset) {
 	return FCB_SUCCESS;
 }
 
-Bit8u DOS_FCBRandomRead(Bit16u seg,Bit16u offset,Bit16u numRec,bool restore) {
+Bit8u DOS_FCBRandomRead(Bit16u seg,Bit16u offset,Bit16u * numRec,bool restore) {
 /* if restore is true :random read else random blok read. 
  * random read updates old block and old record to reflect the random data
  * before the read!!!!!!!!! and the random data is not updated! (user must do this)
  * Random block read updates these fields to reflect the state after the read!
  */
-
-/* BUG: numRec should return the amount of records read! 
- * Not implemented yet as I'm unsure how to count on error states (partial/failed) 
- */
-
 	DOS_FCB fcb(seg,offset);
 	Bit32u random;
 	Bit16u old_block=0;
 	Bit8u old_rec=0;
 	Bit8u error=0;
+	Bit16u count;
 
 	/* Set the correct record from the random data */
 	fcb.GetRandom(random);
 	fcb.SetRecord((Bit16u)(random / 128),(Bit8u)(random & 127));
 	if (restore) fcb.GetRecord(old_block,old_rec);//store this for after the read.
 	// Read records
-	for (int i=0; i<numRec; i++) {
-		error = DOS_FCBRead(seg,offset,(Bit16u)i);
-		if (error!=0x00) break;
+	for (count=0; count<*numRec; count++) {
+		error = DOS_FCBRead(seg,offset,count);
+		if (error!=FCB_SUCCESS) break;
 	}
+	if (error==FCB_READ_PARTIAL) count++;	//partial read counts
+	*numRec=count;
 	Bit16u new_block;Bit8u new_rec;
 	fcb.GetRecord(new_block,new_rec);
 	if (restore) fcb.SetRecord(old_block,old_rec);
@@ -1101,13 +1099,14 @@ Bit8u DOS_FCBRandomRead(Bit16u seg,Bit16u offset,Bit16u numRec,bool restore) {
 	return error;
 }
 
-Bit8u DOS_FCBRandomWrite(Bit16u seg,Bit16u offset,Bit16u numRec,bool restore) {
+Bit8u DOS_FCBRandomWrite(Bit16u seg,Bit16u offset,Bit16u * numRec,bool restore) {
 /* see FCB_RandomRead */
 	DOS_FCB fcb(seg,offset);
 	Bit32u random;
 	Bit16u old_block=0;
 	Bit8u old_rec=0;
 	Bit8u error=0;
+	Bit16u count;
 
 	/* Set the correct record from the random data */
 	fcb.GetRandom(random);
@@ -1115,10 +1114,11 @@ Bit8u DOS_FCBRandomWrite(Bit16u seg,Bit16u offset,Bit16u numRec,bool restore) {
 	if (restore) fcb.GetRecord(old_block,old_rec);
 	if (numRec>0) {
 		/* Write records */
-		for (int i=0; i<numRec; i++) {
-			error = DOS_FCBWrite(seg,offset,(Bit16u)i);// dos_fcbwrite return 0 false when true...
-			if (error!=0x00) break;
+		for (count=0; count<*numRec; count++) {
+			error = DOS_FCBWrite(seg,offset,count);// dos_fcbwrite return 0 false when true...
+			if (error!=FCB_SUCCESS) break;
 		}
+		*numRec=count;
 	} else {
 		DOS_FCBIncreaseSize(seg,offset);
 	}