New config.sys (config.c, config.txt) options: IDLEHALT=n to activate

"HLT on idle" (dosidle.asm, int2f.asm) and KEYBUF=n[,m] to relocate
the keyboard buffer to another area in the 40:ac..40:1ff range. Global
functions and variables: proto.h DosIdle_hlt, init-mod.h and globals.h
DosIdle_hlt() and HaltCpuWhileIdle.


git-svn-id: https://svn.code.sf.net/p/freedos/svn/kernel/trunk@1339 6ac86273-5f31-0410-b378-82cca8765d1b

docs/config.txt

@@ -125,6 +125,23 @@ A good number is 20, though some programs suggest/require
 30, 40, or even 255
 e.g.  files=20
 
+IDLEHALT
+Usage: idlehalt=n
+where n can be -1, 0, 1 or higher (default 0)
+Activates built-in kernel energy saving functionality if n is
+not 0. Value -1 enables all hooks, 1 enables only "safe" hooks,
+CPU halted only if kernel is waiting for CON char device input.
+Further hooks for n=-1 and n>0 depend on the kernel version:
+In addition to the safe hooks, other hooks can get activated,
+for example one for int 0x2f, ax=0x1680 "release time slice".
+Note: In rare cases, entering or leaving HLT mode (which causes
+      big changes in CPU power consumption) can cause crashes if
+      cheap power supplies or mainboards cannot properly filter
+      the transients. Underclocking the whole system may help.
+      Linux always does a few HLT at boot time, to force a hang
+      on buggy systems early (boot with no-hlt to disable HLT).
+P90 may have buggy HLT? www.tavi.co.uk/ps2pages/ohland/halt.html
+
 INSTALL
 INSTALLHIGH
 Usage:  install=[d:][path]file [options]
@@ -135,6 +152,18 @@ to documentation that came with your particular software for
 supported options and usage.
 e.g.  install=nansi.com
 
+KEYBUF
+Usage: keybuf=n[,m]
+where n is in 0xac-0xde or 0x106-0x1de range and m is <= 0x200
+Relocate keyboard buffer from the default location at
+0x40:0x1e-0x3e to 0x40:n-m. The buffer must be more
+than 32 bytes and must not touch offsets 0x100-0x105.
+Default for m is "next multiple of 0x100 after n".
+Note: Some BIOSes store data in the 0xac-0xff area. BASICA will
+      use the 0x106-0x120 area. Other hardware, drivers or apps
+      can collide with KEYBUF, too, so use it at your own risk.
+A reasonably safe choice should be "keybuf=0x140,0x1c0".
+
 LASTDRIVE
 LASTDRIVEHIGH
 Usage:  lastdrive=x 

kernel/config.c

@@ -180,6 +180,7 @@ STATIC VOID DeviceHigh(BYTE * pLine);
 STATIC VOID Files(BYTE * pLine);
 STATIC VOID FilesHigh(BYTE * pLine);
 STATIC VOID Fcbs(BYTE * pLine);
+STATIC VOID CfgKeyBuf(BYTE * pLine);
 STATIC VOID CfgLastdrive(BYTE * pLine);
 STATIC VOID CfgLastdriveHigh(BYTE * pLine);
 STATIC BOOL LoadDevice(BYTE * pLine, char FAR *top, COUNT mode);
@@ -218,6 +219,7 @@ STATIC VOID Stacks(BYTE * pLine);
 STATIC VOID StacksHigh(BYTE * pLine);
 
 STATIC VOID SetAnyDos(BYTE * pLine);
+STATIC VOID SetIdleHalt(BYTE * pLine);
 STATIC VOID Numlock(BYTE * pLine);
 STATIC BYTE * GetNumArg(BYTE * pLine, COUNT * pnArg);
 BYTE *GetStringArg(BYTE * pLine, BYTE * pszString);
@@ -274,6 +276,7 @@ STATIC struct table commands[] = {
   {"DOS", 1, Dosmem},
   {"DOSDATA", 1, DosData},
   {"FCBS", 1, Fcbs},
+  {"KEYBUF", 1, CfgKeyBuf},	/* ea */
   {"FILES", 1, Files},
   {"FILESHIGH", 1, FilesHigh},
   {"LASTDRIVE", 1, CfgLastdrive},
@@ -287,6 +290,7 @@ STATIC struct table commands[] = {
   {"SCREEN", 1, sysScreenMode},   /* JPP */
   {"VERSION", 1, sysVersion},     /* JPP */
   {"ANYDOS", 1, SetAnyDos},       /* tom */
+  {"IDLEHALT", 1, SetIdleHalt},   /* ea  */
 
   {"DEVICE", 2, Device},
   {"DEVICEHIGH", 2, DeviceHigh},
@@ -740,7 +744,6 @@ STATIC struct table * LookUp(struct table *p, BYTE * token)
             0xHH.. : scancode in upper  half
             0x..LL : asciicode in lower half
 */
-
 #define GetBiosTime() peekl(0, 0x46c)
 
 UWORD GetBiosKey(int timeout)
@@ -757,12 +760,17 @@ UWORD GetBiosKey(int timeout)
       init_call_intr(0x16, &r);
       if (!(r.flags & FLG_ZERO))
         return r.a.x;
-    }
+      if (HaltCpuWhileIdle!=0) DosIdle_hlt(); /* not _int */
-    while ((unsigned)(GetBiosTime() - startTime) < timeout * 18u);
+    } while ((unsigned)(GetBiosTime() - startTime) < timeout * 18u);
     return 0xffff;
   }
 
   /* blocking wait (timeout < 0): fetch it */
+  do {
+      if (HaltCpuWhileIdle!=0) DosIdle_hlt(); /* not _int */
+      r.a.x = 0x0100;
+      init_call_intr(0x16, &r);
+  } while (r.flags & FLG_ZERO);
   r.a.x = 0x0000;
   init_call_intr(0x16, &r);
   return r.a.x;
@@ -1153,6 +1161,48 @@ STATIC VOID Fcbs(BYTE * pLine)
     Config.cfgProtFcbs = Config.cfgFcbs;
 }
 
+/* 
+   Keyboard buffer relocation: KEYBUF=start[,end]
+   Select a new location for the  keyboard buffer  at 0x40:xx,
+   for example 0x40:0xac-0xff, but 0x50:5-0xff ("basica" only?)
+   feels safer? 0x60:0-0xff is scratch, we use it as SHELL PSP.
+   (sys / boot sector load_segment / LOADSEG, exeflat call in
+   makefile, DOS_PSP in mcb.h, main.c P_0, task.c, kernel.asm)
+   (50:e0..ff used as early kernel boot drive / config buffer)
+*/
+STATIC VOID CfgKeyBuf(BYTE * pLine)
+{
+  /*  Format:     KEYBUF = startoffset [,endoffset]    */
+  UWORD FAR *keyfill = (UWORD FAR *) MK_FP(0x40, 0x1a);
+  UWORD FAR *keyrange = (UWORD FAR *) MK_FP(0x40, 0x80);
+  COUNT startbuf, endbuf;
+
+  if ((pLine = GetNumArg(pLine, &startbuf)) == 0)
+    return;
+  pLine = skipwh(pLine);
+  endbuf = (startbuf | 0xff)+1;	/* default end: end of the same "page" */
+  if (*pLine == ',')
+  {
+    if ((pLine = GetNumArg(++pLine, &endbuf)) == 0)
+      return;
+  }
+  startbuf &= 0xfffe;
+  endbuf &= 0xfffe;
+  if (endbuf<startbuf || (endbuf-startbuf)<=0x20 ||
+    ((startbuf & 0xff00) != ((endbuf-1) & 0xff00)) )
+    startbuf = 0;		/* flag as bad: too small or page wrap */
+  if (startbuf<0xac || (startbuf>=0x100 && startbuf<0x105) || startbuf>0x1de)
+  {				/* 50:0 / 50:4 are for prtscr / A:/B: DJ */
+    printf("Must start at 0xac..0x1de, not 0x100..0x104\n");
+    return;
+  }
+  keyfill[0] = startbuf;
+  keyfill[1] = startbuf;
+  keyrange[0] = startbuf;
+  keyrange[1] = endbuf;
+  keycheck();
+}
+
 /*      LoadCountryInfo():
  *      Searches a file in the COUNTRY.SYS format for an entry
  *      matching the specified code page and country code, and loads
@@ -1161,7 +1211,6 @@ STATIC VOID Fcbs(BYTE * pLine)
  *
  *      Returns TRUE if successful, FALSE if not.
  */
-
 #if 0
 STATIC BOOL LoadCountryInfo(char *filename, UWORD ctryCode, UWORD codePage)
 {
@@ -1744,29 +1793,36 @@ STATIC void config_init_fnodes(int f_nodes_cnt)
 }
 
 /*
-    Undocumented feature: 
+    Undocumented feature:  ANYDOS 
-    
-    ANYDOS 
         will report to MSDOS programs just the version number
         they expect. be careful with it!
 */
-
 STATIC VOID SetAnyDos(BYTE * pLine)
 {
   UNREFERENCED_PARAMETER(pLine);
   ReturnAnyDosVersionExpected = TRUE;
 }
 
+/*
+   Kernel built-in energy saving: IDLEHALT=haltlevel
+   -1 max savings, 0 never HLT, 1 safe kernel only HLT,
+   2 (3) also hooks int2f.1680 (and sets al=0)
+*/
+STATIC VOID SetIdleHalt(BYTE * pLine)
+{
+  COUNT haltlevel;
+  if (GetNumArg(pLine, &haltlevel))
+    HaltCpuWhileIdle = haltlevel; /* 0 for no HLT, 1..n more, -1 max */
+}
+
 STATIC VOID CfgIgnore(BYTE * pLine)
 {
   UNREFERENCED_PARAMETER(pLine);
 }
 
 /*
-   'MENU'ing stuff
+   'MENU'ing stuff   
-   
+   although it's worse then MSDOS's , its better then nothing    
-   although it's worse then MSDOS's , its better then nothing 
-   
 */
 
 STATIC void ClearScreen(unsigned char attr);

kernel/dosidle.asm

@@ -34,17 +34,32 @@ PSP_USERSS      equ     30h
 segment HMA_TEXT
 
                 global  _DosIdle_int
-
+                global  _DosIdle_hlt
 
                 extern   _InDOS:wrt DGROUP
                 extern   _cu_psp:wrt DGROUP
                 extern   _MachineId:wrt DGROUP
                 extern   critical_sp:wrt DGROUP
                 extern   _user_r:wrt DGROUP
+		; variables as the following are "part of" module inthndlr.c
+		; because of the define MAIN before include globals.h there!
+                extern   _HaltCpuWhileIdle:wrt DGROUP
                 extern   _DGROUP_:wrt HMA_TEXT
 ;
+_DosIdle_hlt:
+                push    ds
+                mov     ds, [cs:_DGROUP_]
+                cmp     byte [_HaltCpuWhileIdle],1
+                jb      DosId0
+                pushf
+                sti
+                hlt                ; save some energy :-)
+                popf
+DosId0:         pop     ds
+                retn
 ;
 _DosIdle_int:
+                call    _DosIdle_hlt
                 push    ds
                 mov     ds, [cs:_DGROUP_]
                 cmp     byte [_InDOS],1
@@ -76,3 +91,6 @@ Do_DosI:
                 pop     ax
                 ret
 
+; segment _DATA		; belongs to DGROUP
+; whatever	db whatever
+

kernel/globals.h

@@ -229,7 +229,7 @@ Freeman Publishing, Lawrence KS, USA (ISBN 0-87930-436-7).\n\
  ;
 
 /* Globally referenced variables - WARNING: ORDER IS DEFINED IN         */
-/* KERNAL.ASM AND MUST NOT BE CHANGED. DO NOT CHANGE ORDER BECAUSE THEY */
+/* KERNEL.ASM AND MUST NOT BE CHANGED. DO NOT CHANGE ORDER BECAUSE THEY */
 /* ARE DOCUMENTED AS UNDOCUMENTED (?) AND HAVE MANY  PROGRAMS AND TSRs  */
 /* ACCESSING THEM                                                       */
 
@@ -420,8 +420,10 @@ void setvec(unsigned char intno, intvec vector);
 #pragma aux (cdecl) spawn_int23 aborts;
 #endif
 void ASMCFUNC spawn_int23(void);        /* procsupt.asm */
+void ASMCFUNC DosIdle_hlt(void);        /* dosidle.asm */
 
 GLOBAL BYTE ReturnAnyDosVersionExpected;
+GLOBAL BYTE HaltCpuWhileIdle;
 
 GLOBAL struct f_node fnode[2];
 GLOBAL int fnode_fd[2];

kernel/init-mod.h

@@ -155,6 +155,9 @@ unsigned init_oem(void);
 void movebda(size_t bytes, unsigned new_seg);
 unsigned ebdasize(void);
 
+/* dosidle.asm */
+extern void ASM DosIdle_hlt(VOID);
+
 /* intr.asm */
 
 /*
@@ -257,7 +260,8 @@ extern BYTE DOSFAR ASM _HMATextAvailable,    /* first byte of available CODE are
   FAR ASM _HMATextStart[],          /* first byte of HMAable CODE area      */
   FAR ASM _HMATextEnd[], DOSFAR ASM break_ena;  /* break enabled flag                   */
 extern BYTE DOSFAR _InitTextStart,       /* first available byte of ram          */
-  DOSFAR ReturnAnyDosVersionExpected;
+  DOSFAR ReturnAnyDosVersionExpected,
+  DOSFAR HaltCpuWhileIdle;
 
 extern BYTE FAR ASM internal_data[];
 extern unsigned char FAR ASM kbdType;

kernel/int2f.asm

@@ -28,11 +28,12 @@
 ; $Id$
 ;
 
-		%include "segs.inc"
+        %include "segs.inc"
         %include "stacks.inc"
 
 segment	HMA_TEXT
-            extern  _cu_psp:wrt DGROUP
+            extern _cu_psp:wrt DGROUP
+            extern _HaltCpuWhileIdle:wrt DGROUP
             extern _syscall_MUX14
 
             extern _DGROUP_
@@ -53,9 +54,29 @@ Int2f2:
                 stc
 FarTabRetn:
                 retf    2                       ; Return far
-Int2f3:
+
+WinIdle:					; only HLT if at haltlevel 2+
+		push	ds
+                mov     ds, [cs:_DGROUP_]
+		cmp	byte [_HaltCpuWhileIdle],2
+		pop	ds
+		jb	FarTabRetn
+		pushf
+		sti
+		hlt				; save some energy :-)
+		popf
+		push	ds
+                mov     ds, [cs:_DGROUP_]
+		cmp	byte [_HaltCpuWhileIdle],3
+		pop	ds
+		jb	FarTabRetn
+		mov	al,0			; even admit we HLTed ;-)
+		jmp	short FarTabRetn
+
+Int2f3:         cmp     ax,1680h                ; Win "release time slice"
+                je      WinIdle
                 cmp     ah,16h
-                je      FarTabRetn              ; Win Hook return fast
+                je      FarTabRetn              ; other Win Hook return fast
                 cmp     ah,12h
                 je      IntDosCal               ; Dos Internal calls
 

kernel/proto.h

@@ -120,10 +120,12 @@ int get_sft_idx(UCOUNT hndl);
 struct cds FAR *get_cds(unsigned dsk);
 COUNT DosTruename(const char FAR * src, char FAR * dest);
 
-/*dosidle.asm */
+/* dosidle.asm */
 VOID ASMCFUNC DosIdle_int(void);
+VOID ASMCFUNC DosIdle_hlt(void);
 #ifdef __WATCOMC__
 #pragma aux (cdecl) DosIdle_int modify exact []
+#pragma aux (cdecl) DosIdle_hlt modify exact []
 #endif
 
 /* dosnames.c */