I've restructured the alternative version of PDP-7 Unix so that the

source code is now in src/alt. All the files in src/sys and src/cmd
are only annotated versions of the files in scans/.
The build/Makefile has been updated so that it can build the
original PDP-7 Unix or the alternative version.
Phil has fixed the Graphics-2 code, so that there is no need to
have any #ifdef code in the original kernel.

src/cmd/init.s

@@ -124,11 +124,7 @@ login:
 2:
    lac nchar
    sys setuid		" Set the user's user-id
-#ifdef NO_DD
-   sys chdir; dotdot	" Change into the root directory (out of system)
-#else
    sys chdir; dd	" Change into the "dd" directory
-#endif
    sys chdir; dir	" and then the user's home directory
 
    lac d2		" Close file descriptor 2
@@ -253,8 +249,6 @@ m3:
 m3s = .-m3
 dd:
    <dd>;040040;040040;040040
-dotdot:
-   <..>;040040;040040;040040
 dir:
    040040;040040;040040;040040
 

src/minikern/README.md

@@ -1,8 +0,0 @@
-#Readme
-
-This area is a place to write and try out kernel-mode test code. We can
-try out drivers, test the disk routines etc. The idea is to bring pieces
-of the real kernel in, test them, and keep incorporating stuff until we
-reach a working kernel.
-
-List filenames and comments here.

src/minikern/ttyout_test.s

@@ -1,71 +0,0 @@
-" Code to test the teleprinter output. Some code borrowed from s7.s
-
-iof = 0700002                   " PIC: interrupts off
-ion = 0700042                   " PIC: interrupts on
-tsf = 0700401                   " TTY: skip if flag set
-tcf = 0700402                   " TTY: clear flag
-tls = 0700406                   " TTY: load buffer, select
-
-. = 020
-
-   iof			" Interrupts off, do we need this?
-
-1: tsf			" Is the teleprinter ready to print?
-   jmp 1b		" No, loop back
-
-   tcf			" Clear the ready flag
-   jms ttyrestart	" Print out a character
-   hlt			" and halt for now
-
-
-ttyrestart: 0
-   lac ttydelay		" Is the ttydelay positive?
-   spa
-     jmp ttyrestart i	" Yes, can't print the character yet
-   lac nttychar
-   dzm nttychar
-   sza
-     jmp 3f
-   isz ttydelay		" Increment the tty delay towards zero
-   lac d2		" Why 2?
-   jms getchar		" Get a character to print
-     jmp 2f		" Why the jump, does getchar skip? Yes if no char
-3:
-   tls			" Send the character to the teleprinter
-   sad o12
-     jms putcr		" It's a newline, also send a CR?
-   sad o15
-     skp		" It was CR, so now insert a delay
-   jmp ttyrestart i	" Not CR, so return from the routine
-
-   lac ttydelay		" Add 020 to the ttydelay
-   tad o20
-   rcr			" Rotate right once
-   cma			" Invert the AC
-   dac ttydelay		" and save back in ttydelay
-   jmp ttyrestart i	" Now return from the routine
-2:
-   " lac sfiles+1
-   " jms wakeup
-   " dac sfiles+1
-   jmp ttyrestart i	" Now return from the routine
-
-getchar: 0
-   lac d65		" For now, return ASCII A
-   isz getchar
-   jmp i getchar
-
-putcr: 0
-   lac o15
-   dac nttychar
-   cla
-   jmp putcr i
-
-d2: 2
-d65: 64
-o12: 012
-o15: 015
-o20: 020
-
-ttydelay: 0
-nttychar: .=.+1

src/other/wktchrm.s

@@ -1,41 +0,0 @@
-" Alternative chrm: chrm file [file file ...]
-"
-" Unlink the named files
-
-   lac 017777			" Go to the argc
-   tad d1			" Skip past the argc
-   dac 2f			" Save pointing at cmd name, we will skip later
-   lac 017777 i			" How many arguments do we have?
-   sad d4
-     sys exit			" None, so exit
-   tad dm4			" Subtract 1
-   dac 017777 i			" and save in the argc
-
-1:
-   lac 017777 i			" Any arguments left?
-   sna
-     sys exit			" No, exit the program
-   tad dm4			" Subtract 4 from the argc and update it
-   dac 017777 i
-   lac 2f			" Move up to the next filename
-   tad d4
-   dac 2f			" and save it in the unlink arg
-   sys unlink; 2:0		" Unlink the file
-   sma
-     jmp 1b			" Loop back if the unlink was OK, or issue err
-   lac 2b			" Copy the filename pointer below
-   dac 2f
-   lac d1			" Write the filename on stdout
-   sys write; 2:0; 4
-   lac d1
-   sys write; 1f; 2		" Write " ?\n" on stdout
-   jmp 1b			" and loop back
-
-1:
-   040077;012000		" String literal " ?\n"
-dd:
-   <dd>;040040;040040;040040	" Filename dd
-d1: 1
-d4: 4
-d5: 5
-dm4: -4

src/sys/s2.s

@@ -6,11 +6,6 @@
 	"   sys status; dir_name_ptr; file_name_ptr
 	"   NO_DD version: sys status; file_name_ptr
 .status:
-#ifdef NO_DD
-   jms arg			" fetch file name pointer
-   dac .+3
-   lac u.cdir			" get current working directory
-#else
    jms arg			" fetch directory name pointer
    dac .+5
    jms arg			" fetch file name pointer
@@ -18,7 +13,6 @@
    lac u.cdir			" get current working directory
    jms namei; ..		" look up source directory
       jms error			"  not found: return error to user
-#endif
    jms namei; ..		" look up file
       jms error			"  not found: return error
    jms iget			" read file inode
@@ -110,11 +104,7 @@
    dac 1f
    jms arg
    dac 2f
-#ifdef NO_DD
-   lac u.cdir			" Search the current directory
-#else
    lac d4			" Search the directory at i-num 4
-#endif
    jms namei; 0:0		" for the first argument
       jms error			" Didn't find it
    jms namei; 1:0		" In the i-num found by 1st namei,

src/sys/s7.s

@@ -4,8 +4,6 @@
 pibreak:			" priority interrupt break processing "chain"
    dac .ac			" save interrupt AC
 	"** CROSSED OUT....
-
-#ifdef GRAPHICS2
    dpsf
    jmp 1f		" disable the Graphics-2 I/O
 
@@ -26,7 +24,6 @@ pibreak:			" priority interrupt break processing "chain"
    -1
    dac dpwrite
    jmp piret	"** END OF CROSSOUT
-#endif
 
 1: clsf			" clock overflow (line frequency ticks)?
    jmp 1f		"  no
@@ -90,7 +87,6 @@ cnop:			" fetched as constant in iread
    dac .dspb
    jmp piret
 dsprestart:
-#ifdef GRAPHICS2
    lac d1
    dac .dspb			" set .dsbp = 1
    lac dspbufp			" load display buf pointer
@@ -109,7 +105,6 @@ dsprestart:
    dac .lpba			" save
    rlpd				" G-2: resume after light pen stop
    jmp piret
-#endif
 
 1: ksf				" (TTY) keyboard flag set?
    jmp 1f			"  no