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changeset 2585:75847753c6a3

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Cleaned up code and removed multiple calculations of shift divisor by calculating it once and storing it in data. Corrected sector count calculation to include partial clusters.
author robertgault
date Mon, 19 Sep 2011 20:51:28 +0000
parents f7f97fe766e3
children d706cc0dfd58
files level1/cmds/cobbler.asm level1/cmds/os9gen.asm
diffstat 2 files changed, 136 insertions(+), 114 deletions(-) [+]
line wrap: on
line diff
--- a/level1/cmds/cobbler.asm	Fri Sep 16 12:54:58 2011 +0000
+++ b/level1/cmds/cobbler.asm	Mon Sep 19 20:51:28 2011 +0000
@@ -24,6 +24,12 @@
 *        2011/09/16 Robert Gault
 * Corrected a typo which occured when committing code. Exit of Initcalc had
 * ABM3 in wrong place.
+*
+*        2011/09/18 Robert Gault
+* Cleaned up code and removed multiple calculations of shift divisor by
+* calculating it once and storing it in data.
+* Corrected sector count calculation to include partial clusters.
+
 
          nam   Cobbler
          ttl   Write OS9Boot to a disk
@@ -33,7 +39,7 @@
 *The next line needed for stand-alone compiling. It should not
 * be present in the NitrOS-9 project.
 
-*Level    equ	2
+Level    equ	2
 
          IFP1
          use   defsfile
@@ -44,7 +50,7 @@
 tylg     set   Prgrm+Objct   
 atrv     set   ReEnt+rev
 rev      set   $00
-edition  set   8
+edition  set   9
 
          mod   eom,name,tylg,atrv,start,size
 
@@ -52,7 +58,9 @@
 lsn0buff 	rmb   26	Buffer to hold data from LSN0 of traget device
 newbpath 	rmb   1
 devpath  	rmb   3
-EndDevName    	rmb   2		pointer to last character of device name when moving to fullbnam
+EndDevName  rmb   2		pointer to last character of device name when moving to fullbnam
+btshift     rmb   2         division factor
+bitflag     rmb   1         indicates fractional division
 fullbnam 	rmb   20	this buffer hodls the entire name (i.e. /D0/OS9Boot)
 u0034    	rmb   16
 BootBuf    	rmb   7		Area to read part of current boot area into, to check for boot stuff
@@ -94,9 +102,9 @@
          fcc   "Error - cannot gen to hard disk"
          fcb   C$CR
 SeekErr	 fcb	C$LF
-	 fcc	"Error seeking sector"
-	 fcb	C$CR	 
-	IFNE	DRAGON
+	   fcc	"Error seeking sector"
+	   fcb	C$CR	 
+	 IFNE	DRAGON
 FileWarn fcb   C$LF
          fcc   "Warning - not a Dragon "
          fcb   C$LF
@@ -179,15 +187,14 @@
          lda   <devpath
          os9   I$Read   		read LSN0
          lbcs  Bye			Error : exit
-
-	ifeq	0
+         lbsr  FShift                   get divisor from DD.BIT R.G.
+         sty   btshift,u
 * Request memory fot the FAT buffer + 256 bytes for stack space R.G.
          ldd	<DD.MAP
          addd	#size+256
          os9	F$Mem
          lbcs	NoMem
-	 tfr	y,s
-	endc
+	   tfr	y,s
 
          ldd   <DD.BSZ			get size of bootfile currently
          beq   L019F			branch if none
@@ -195,7 +202,7 @@
          leax  <fullbnam,u
          os9   I$Delete 		delete existing bootfile
          
-	 clra  
+	   clra  
          clrb  
          sta   <DD.BT			Init some of the LSN0 vars
          std   <DD.BT+1
@@ -303,7 +310,7 @@
          puls  u
          lbcs  Bye			Error: exit
 	 
-         leax  <bffdbuf,u		Point to buffer for filedes sector
+         leax  bffdbuf,u		Point to buffer for filedes sector
          ldy   #256
          os9   I$Read   		read in filedes sector
          lbcs  Bye			Error: exit
@@ -384,7 +391,7 @@
 	ENDC
 
 RewriteBitmap    
-	ldd   #$0001
+	   ldd   #$0001
          lbsr  Seek2LSN			Seek to bitmap sector on disk
          leax  >bitmbuf,u
          ldy   <DD.MAP
@@ -452,7 +459,7 @@
 
 * Determine bit shift from DD.BIT
 * Return shift in regY needed for division R.G.
-FShift
+FShift   pshs   d
 	 ldd	lsn0buff+DD.BIT,u		get sectors per cluster
          ldy	#-1
 * This finds number of bit shifts for DD.BIT
@@ -461,15 +468,15 @@
          leay	1,y
          cmpd	#0
          bne	SF1
-         rts
+         puls   d,pc
 
-* Returns bit in bitmap corresponding to LSN in regA
-* X=bitmap buffer, on exit X points to bitmap byte of our LSN
+* Enter: regD=LSN to test,regX=bitmap buffer
+* Exit: regX points to bitmap byte of our LSN
+*       regA=bit mask, regB not preserved
 GetBitmapBit    
 * We need to divide by DD.BITx8 R.G.
-	 pshs y,d
-	 bsr	FShift
-         ldd	,s		recover LSN
+	   pshs y,d
+	   ldy	btshift,u
          cmpy	#0
          beq	GBB3
 * Divide LSN by DD.BIT
@@ -478,8 +485,8 @@
          leay	-1,y
          bne	GBB2
 GBB3     stb	,s		save lsb
-	 andb	#7		Make sure offset within table
-	 stb	1,s		save table mask
+	   andb	#7		Make sure offset within table
+	   stb	1,s		save table mask
          ldy	#3
 * Now regY is the number of right shifts required for 8
          ldb	,s		recover the lsb
@@ -489,7 +496,7 @@
          bne	GBB4
 * Now regD is the byte number in the FAT
          leax	d,x		point regX at the byte
-	 puls	d
+	   puls	d
          leay	<BitTable,pcr	Point to bit table
          lda 	b,y		Get bit from table
          puls	pc,y		Restore regY and return
@@ -497,29 +504,33 @@
 BitTable    fcb   $80,$40,$20,$10,$08,$04,$02,$01	Bitmap bit table
 
 * Common code for CheckAlloc & Allocate moved to subroutine R.G.
+* Enter: see CheckAlloc & Allocate
+* Exit: regY=divisor, regD=LSN
 Initcalc bsr   AbsLSN		go get absolute LSN in D
          leax  >bitmbuf,u	point X to our bitmap buffer
          bsr   GetBitmapBit	regA is bit from table
 * New code to obtain a shift value R.G.
          pshs	d,y
-	 bsr	FShift
-	 cmpy	#0
-	 bne	CA2
-	 puls	d,y
-	 bra	CA3
-CA2	 ldd	2,s		recover regY sector count
+	   ldy	btshift,u
+	   cmpy	#0
+	   bne	CA2
+	   puls	d,y,pc
+CA2      ldd    2,s             recover number of sectors
+         clr    bitflag,u
 * Divide sector count by DD.BIT
 CAloop   lsra
-	 rorb
-	 leay	-1,y
-	 bne	CAloop
-	 cmpd	#0
-	 bne	CAnz
-	 incb			should never be zero bits
-CAnz	 tfr	d,y		regY has been divided by DD.BIT
-	 ldd	,s		recover content
-	 leas	4,s		clean stack
-CA3	 rts
+	   rorb
+	   bcc    CAlp2
+	   inc    bitflag,u	indicate fractional result
+CAlp2	   leay	-1,y
+	   bne	CAloop
+	   tst    bitflag,u
+	   beq	CAnz
+	   incb			include partial cluster
+CAnz	   tfr	d,y		regY has been divided by DD.BIT
+	   ldd	,s		recover content
+	   leas	4,s		clean stack
+	   rts
 
 *
 * CheckAlloc, check to see if a block of sectors is allocated.
@@ -529,10 +540,10 @@
 *
 * I think regY needs to be divided by DD.BIT R.G.
 CheckAlloc
-	pshs  y,x,b,a
-	bsr   Initcalc
+	   pshs  y,x,b,a
+	   bsr   Initcalc
 * Back to older code
-	 sta   ,-s		save off
+	   sta   ,-s		save off
          bmi   L03CB
 	 
          lda   ,x		Get bitmap byte of our LSN
@@ -540,14 +551,14 @@
 L03BB    anda  ,s		Is our LSN allocated ?
          bne   L03F7		Yes : flag error
          
-	 leay  -$01,y		Decrement sector count		
+	   leay  -$01,y		Decrement sector count		
          beq   L03F3		All done : yes, exit
          
-	 lda   <LSNBitmapByte	Get saved bitmap byte
+	   lda   <LSNBitmapByte	Get saved bitmap byte
          lsr   ,s		Check next sector
          bcc   L03BB		If carry, we need to fetch next byte from bitmap
          
-	 leax  $01,x		Increment bitmap pointer
+	   leax  $01,x		Increment bitmap pointer
 L03CB    lda   #$FF		
          sta   ,s
          bra   L03DB
@@ -556,7 +567,7 @@
          anda  ,s
          bne   L03F7
          
-	 leax  $01,x
+	   leax  $01,x
          leay  -$08,y
 L03DB    cmpy  #$0008		Done a whole byte's worth of blocks ?
          bhi   L03D1		Yes
@@ -567,7 +578,7 @@
          leay  -$01,y		decrement sector count
          bne   L03E5		Any more : yes continue
          
-	 coma  
+	   coma  
          sta   ,s
 L03ED    lda   ,x
          anda  ,s
@@ -587,8 +598,8 @@
 *
 * I think regY should be divided by DD.BIT R.G.
 Allocate    
-	 pshs  y,x,b,a
-	 bsr   Initcalc
+	   pshs  y,x,b,a
+	   lbsr   Initcalc
 * Back to old code
          sta   ,-s		Save it
          bmi   L041C
@@ -651,7 +662,7 @@
          lda   <devpath
          os9   I$Seek   	Seek to LSN0
          
-	 puls  u		added for OS-9 Level One +BGP+
+	   puls  u		added for OS-9 Level One +BGP+
          leax  lsn0buff,u	Point to our LSN buffer
          ldy   #DD.DAT
          lda   <devpath
@@ -668,7 +679,7 @@
          ENDC
 	 
 DisplayErrorAndExit    
-	pshs  b
+	   pshs  b
          lda   #$02
          ldy   #256
          os9   I$WritLn 
@@ -683,16 +694,16 @@
 WriteBad leax  >WritErr,pcr
          clrb  
          bra   DisplayErrorAndExit
-SeekBad	leax	SeekErr,pcr
-	clrb
-	bsr	DisplayErrorAndExit
+SeekBad  leax  SeekErr,pcr
+	   clrb
+	   bsr   DisplayErrorAndExit
 TrkAlloc leax  >FileWarn,pcr
          clrb  
          bra   DisplayErrorAndExit
 
-NoMem	leax	>MemSpace,pcr
-	clrb
-	bra	DisplayErrorAndExit
+NoMem	  leax   >MemSpace,pcr
+	  clrb
+	  bra    DisplayErrorAndExit
 
          IFGT  Level-1
 NoRel    leax  >RelMsg,pcr
--- a/level1/cmds/os9gen.asm	Fri Sep 16 12:54:58 2011 +0000
+++ b/level1/cmds/os9gen.asm	Mon Sep 19 20:51:28 2011 +0000
@@ -41,6 +41,11 @@
 * 14       2011/09/16 Robert Gault
 * Corrected a typo which occured when committing code. Exit of Initcalc had
 * ABM3 in wrong place. Also included C$CR in file name copy.
+*
+*         2011/09/18 Robert Gault
+* Cleaned up code and removed multiple calculations of shift divisor by
+* calculating it once and storing it in data.
+* Corrected sector count calculation to include partial clusters.
 
          nam   OS9Gen
          ttl   OS-9 bootfile generator
@@ -48,7 +53,7 @@
 * Disassembled 02/07/06 13:11:11 by Disasm v1.6 (C) 1988 by RML
 
 *Needed for stand alone compile
-*LEVEL    equ   2
+LEVEL    equ   2
 
          IFP1
          use   defsfile
@@ -91,6 +96,8 @@
 eflag    rmb   1
 sngldrv  rmb   1
 bootdev  rmb   32
+btshift  rmb   2
+bitflag  rmb   1
 lsn0     rmb   26
 btfstr   rmb   160
 u007B    rmb   2
@@ -405,6 +412,8 @@
          ldy   #256
          os9   I$Read   	read LSN0
          bcs   L033C
+         lbsr	FShift
+         sty	btshift,u	save divisor value R.G.
 L0361    lda   <bfpath		get bootfile path in A
          leax  >u047E,u
          ldy   <u0013
@@ -548,19 +557,19 @@
          ldd   #$0001
          lbsr  Seek2LSN
 *        leax  sectbuff,u		R.G. Expand memory to hold buffer
-	 ldd	<lsn0+DD.MAP,u
-	 addd	#bitmbuf+256		expand memory by DD.MAP+256 bytes
-	 os9	F$Mem
-	 leax	MemErr,pcr
-	 lbcs	WritExit
-	 tfr	y,s			relocate stack
+	   ldd   <lsn0+DD.MAP,u
+	   addd  #bitmbuf+256		expand memory by DD.MAP+256 bytes
+	   os9   F$Mem
+	   leax  MemErr,pcr
+	   lbcs  WritExit
+	   tfr   y,s			relocate stack
 
 *        leax  sectbuff,u
-	 leax	bitmbuf,u
+	   leax  bitmbuf,u
          ldy   <lsn0+DD.MAP,u	get number of bytes in device's bitmap
          lda   <devpath
          os9   I$Read   	read the FAT into the bitmbuf
-         leax	TrkErr,pcr
+         leax  TrkErr,pcr
          lbcs  WritExit
 
          ldd   #Bt.Track*256	boot track regD=$2200
@@ -606,7 +615,7 @@
          ldd   #$0001
          lbsr  Seek2LSN
 *         leax  sectbuff,u
-	 leax	bitmbuf,u
+	   leax   bitmbuf,u
          ldy   <lsn0+DD.MAP,u	get number of bytes in device's bitmap
          lda   <devpath
          os9   I$Write  		write out the bitmap
@@ -724,81 +733,83 @@
 
 * Determine bit shift from DD.BIT R.G.
 * Return shift in regY needed for division
-FShift
-	 ldd	lsn0+DD.BIT,u		get sectors per cluster
-         ldy	#-1
+FShift   pshs   d
+	   ldd    lsn0+DD.BIT,u		get sectors per cluster
+         ldy    #-1
 * This finds number of bit shifts for DD.BIT R.G.
 SF1      lsra
          rorb
-         leay	1,y
-         cmpd	#0
-         bne	SF1
-         rts
+         leay   1,y
+         cmpd   #0
+         bne    SF1
+         puls   d,pc
 
 
 * Returns bit in bitmap corresponding to LSN in regA
 * X=bitmap buffer, on exit X points to bitmap byte of our LSN
 L05AA    
 * We need to divide by DD.BITx8 R.G.
-	 pshs y,d
-	 bsr	FShift
-         ldd	,s		recover LSN
-         cmpy	#0
-         beq	GBB3
+	   pshs   y,d
+	   ldy    btshift,u
+         cmpy   #0
+         beq    GBB3
 * Divide LSN by DD.BIT R.G.
 GBB2     lsra
          rorb
-         leay	-1,y
-         bne	GBB2
-GBB3     stb	,s		save lsb
-	 andb	#7		Make sure offset within table
-	 stb	1,s		save table mask
-         ldy	#3
+         leay   -1,y
+         bne    GBB2
+GBB3     stb    ,s	save lsb
+	   andb   #7	Make sure offset within table
+	   stb    1,s	save table mask
+         ldy    #3
 * Now regY is the number of right shifts required for 8 R.G.
-         ldb	,s		recover the lsb
+         ldb    ,s	recover the lsb
 GBB4     lsra
          rorb
-         leay	-1,y
-         bne	GBB4
+         leay   -1,y
+         bne    GBB4
 * Now regD is the byte number in the FAT
-         leax	d,x		point regX at the byte
-	 puls	d
-         leay	<BitTable,pcr	Point to bit table
-         lda 	b,y		Get bit from table
-         puls	pc,y		Restore regY and return
+         leax   d,x	point regX at the byte
+	   puls   d
+         leay   <BitTable,pcr	Point to bit table
+         lda    b,y	Get bit from table
+         puls   pc,y	Restore regY and return
 
 BitTable    fcb   $80,$40,$20,$10,$08,$04,$02,$01	Bitmap bit table
 
 * Common routine used by ABMSet & ABMClear  R.G.
+* Enter: see ABMSet & ABMClear
+* Exit: regY=divisor, regD=LSN
 Initcalc bsr   AbsLSN		convert A:B to LSN
-*         leax  sectbuff,u	R.G.
-	 leax	bitmbuf,u
+	   leax  bitmbuf,u
          bsr   L05AA		getbitmapbit
-         pshs	d,y
-	 bsr	FShift		R.G. code to include DD.BIT
-	 cmpy	#0
-	 bne	ABM2
-	 puls	d,y
-	 bra	ABM3
-ABM2	 ldd	2,s		recover regY sector count
+         pshs  d,y
+	   ldy   btshift		R.G. code to include DD.BIT
+	   cmpy  #0
+	   bne   ABM2
+	   puls  d,y,pc
+ABM2	   ldd   2,s		recover regY sector count
+         clr    bitflag,u
 * Divide sector count by DD.BIT
 ABMlp    lsra
-	 rorb
-	 leay	-1,y
-	 bne	ABMlp
-	 cmpd	#0
-	 bne	ABMnz
-	 incb			should never be zero bits
-ABMnz	 tfr	d,y		regY has been divided by DD.BIT
-	 ldd	,s		recover content
-	 leas	4,s		clean stack
-ABM3	 rts
+	   rorb
+	   bcc    ABMlp2
+	   inc    bitflag,u	mark carry over
+ABMlp2   leay   -1,y
+	   bne    ABMlp
+	   tst    bitflag,u
+         beq    ABMnz
+	   incb			include partial cluster
+ABMnz	   tfr   d,y		regY has been divided by DD.BIT 
+	   ldd   ,s		recover content
+	   leas  4,s		clean stack
+ABM3	   rts
 
 
 * Clear bits in the allocation bitmap
 * Entry: A = Track, B = Sector, Y = number of bits to clear
 ABMClear pshs  x,y,b,a
-	 bsr   Initcalc
+	   bsr   Initcalc
 * Back to older code
          sta   ,-s		save map bit
          bmi   L05EA		go if bit #7
@@ -841,7 +852,7 @@
 * Set bits in the allocation bitmap
 * Entry: A = Track, B = Sector, Y = number of bits to set
 ABMSet   pshs  y,x,b,a
-	 lbsr   Initcalc
+	   lbsr   Initcalc
 * Back to old code
          sta   ,-s
          bmi   L063A