hdpmi: fixed int 31h, ax=301h/302h

Author: Baron-von-Riedesel

Src/DPMILDR/DPMILDR.ASM

@@ -80,7 +80,6 @@ endif
 
 ?RESETDEFPATH	= 0	;0 1= reset szPath? No, currently this is done
 					;  every time a .EXE is loaded
-?PSPSAVEI2FADDR	= 007Ch	;address in PSP to save int vector 2Fh
 
 if ?HDPMI
 _COPY2PSP_		= 0
@@ -505,20 +504,6 @@ _TEXT segment
 wLdrDS label word
 	jmp overlayentry
 
-if ?DISABLESERVER	;obsolete
-
-int2frm:
-  if ?HIDENEASWELL
-	cmp ah, 16h
-  else
-	cmp ax, 1687h
-  endif
-	jz @F
-	jmp dword ptr cs:[?PSPSAVEI2FADDR]
-@@:
-	iret
-endif
-
 if _COPY2PSP_
 psp_rou:
 	int 31h		;free extended memory
@@ -1660,32 +1645,26 @@ endif
 int214b_1:
 endif
 	xor cx,cx
-if ?DISABLESERVER
-	call disableserver
-endif
 if ?32BIT
-if ?DOSEMUSUPP
+ if ?DOSEMUSUPP
 	test cs:fMode, FMODE_DOSEMU
 	jz @F
 	call __loadpgm
 	jmp loadpgmdone
 @@:
-endif
+ endif
 endif
 
 ;------------------- here there was code to reset int21
 ;------------------- so the loader does not intercept int 21, ah=4ch
 ;------------------- of the now launched program (if it is a pm app)
 ;------------------- but it seems better to check in int21,ah=4ch
 ;------------------- if the terminating app is one started by the loader
-	call doscall 		  ;exec (real mode) program
+	call doscall 	;exec (real mode) program
 loadpgmdone:
 	pushf
 	@trace_s <lf,"-------------------------------------------",lf>
 	@trace_s <"dpmildr 21-4bh: back from int 21h, ax=4B00h",lf>
-if ?DISABLESERVER
-	call enableserver
-endif
 	popf
 	pushf
 if _LASTRC_
@@ -2002,52 +1981,6 @@ __loadpgm endp
 endif
 endif
 
-if ?DISABLESERVER	;obsolete
-
-disableserver proc uses ds
-if 1
-	mov ds, cs:[wLdrPSP] 
-	mov word ptr ds:[?PSPSAVEI2FADDR+2],0
-endif
-	test cs:[bEnvFlgs], ENVFL_LOAD1APPONLY
-	jz exit
-if 0
-	cmp cs:[wTasks], 0	;is anything loaded at all?
-	jz exit
-endif
-	pusha
-	mov bl, 2fh
-	mov ax, 200h
-	int 31h
-	mov ds:[?PSPSAVEI2FADDR+0],dx
-	mov ds:[?PSPSAVEI2FADDR+2],cx
-	mov cx, cs:[wPSPSegm]
-	mov dx, 0100h+offset int2frm
-	mov ax, 0201h
-	int 31h
-	popa
-exit:
-	ret
-disableserver endp
-
-enableserver proc public uses ds
-	pusha
-	mov ds, cs:[wLdrPSP]
-	xor dx,dx
-	xor cx,cx
-	xchg dx, ds:[?PSPSAVEI2FADDR+0]
-	xchg cx, ds:[?PSPSAVEI2FADDR+2]
-	jcxz @F
-	mov bl, 2fh
-	mov ax, 0201h
-	int 31h
-@@:
-	popa
-	ret
-enableserver endp
-
-endif
-
 if ?SUPAPPTITLE
 
 ;*** prepare call of SetAppTitle

Src/DPMILDR/DPMILDR.INC

@@ -24,8 +24,6 @@ endif
 ?INT23RES		= 1	;1, restore int 23
 ?INT41SUPPORT	= 1	;1, support Int 41h debugging messages
 ?SUPAPPTITLE	= 1	;1, support for "application title" (win9x only, in rm!)
-?DISABLESERVER	= 0	;0, 1=disable DPMI server for next task if DPMILDR=8;
-					;   since HDPMI=32 exists, this is now obsolete
 ?SETDTA			= 1	;1, 1=for ?MULTPSP: init DTA to PSP:80 on start
 ?ZEROHIWORDEBP  = 1	;1, 1=if ?32BIT clear hiword(ebp) before 16-bit proc is called.
 					;   this is essentially for ENTER/LEAVE instructions!

Src/HDPMI/EXCEPT.ASM

@@ -323,11 +323,16 @@ if 0 ;v3.23: reverted - this caused severe problems with exc display in v3.22
 	mov bPICMask, al
 	mov al,-1
 	out 21h, al
-else
 endif
 ;--- v3.22: prevent reentry thru std rmcbs
-;--- v3.23: switch also used to prevent reentry thru internal rmcbs
-	mov [bNoRMCBEntry], 1
+;--- v3.23: switch also used to prevent reentry thru internal rmcbs;
+;---        however, activate switch only if at least one rmcb/irq is active!
+	mov al,0Bh
+	out 20h,al
+	in al,20h
+	cbw
+	or ax,[cRMCB]
+	setnz [bNoRMCBEntry]
 
 if ?SAFERMSTACK
 	push [wHostPSP]

Src/HDPMI/HDPMI.ASM

@@ -3455,6 +3455,7 @@ callrmsint_rm:
 	push cs:[tmpFLReg]
 	call cs:[calladdr2]
 	pushf
+	public callrmsint_brk
 callrmsint_brk::
 	@rm2pmbrk
 	pop cs:[tmpFLReg]
@@ -6151,15 +6152,15 @@ int1588:
 iretwithNC:
 	push bp
 	mov bp,sp
-	and byte ptr [bp+6],not _CY
+	and byte ptr [bp+2].IRETSRM.rFL,not _CY
 	pop bp
 	iret			;real-mode iret!
 if ?WATCHDOG
 iretwithC:
 	popf
 	push bp
 	mov bp,sp
-	or byte ptr [bp+6],_CY
+	or byte ptr [bp+2].IRETSRM.rFL,_CY
 	pop bp
 	iret            ;real-mode iret!
 endif

Src/HDPMI/HDPMIHIS.TXT

@@ -16,6 +16,9 @@
   � setting HDPMI=8192 now runs an INT3 instead of setting the trace flag.
   � fixed regression in v3.22: interrupts are no longer masked during exc
     display, since this may have caused the system to freeze.
+  � fixed: clear IF in current flags for int 31h, ax=302h, alike ax=300h.
+  � fixed: ensure that the real-mode part of int 31h, ax=301h is fully
+    reentrant.
 
   24.03.2025, version 3.22