Merge pull request #35 from philbudne/master

as comments, ops.s

src/cmd/as.s

@@ -125,7 +125,7 @@ init2: 0			" start pass 2
    lac d1
 "** 05-1-4.pdf page 34
    dac passno			" passno = 1
-   sys write; 1f; 2f-1f		" output II
+   sys write; 1f; 2f-1f		" output II\n
    jms init
    lac o17
    sys creat; 2f		" create a.out
@@ -479,9 +479,9 @@ nf1:
    sys open; fname: 0; 0	" open fname
    dac iof			" save fd
    sma				" open ok?
-   lac passno			"  yes, load pass number
-   sna				"   open failed: skip or open ok, pass 2
-   jmp nextfil i		"    pass 1, open OK, return.
+   lac passno			"  yes: load pass number
+   sna				" no: open failed: skip or open ok, pass 2
+   jmp nextfil i		"  pass 1, open OK, return.
    lac fname			" load filename pointer
    dac 1f			" save for write
    lac d1			" stdout

src/cmd/ops.s

@@ -0,0 +1,123 @@
+" ops and system calls from as7; as.s has no initial symbol table
+" so this needs to be included in any assembly of user programs
+
+" "sys" has it's own sop.s which includes I/O instructions, but lacks
+" system call definitions, and lacks some instructions used in
+" commands but not in the kernel, so it can't have been the file used
+" for user assemblies.
+
+save   = 1		" saves core dump & user area!
+getuid = 2
+open   = 3
+read   = 4
+write  = 5
+creat  = 6
+seek   = 7
+tell   = 8
+close  = 9
+link   = 10
+unlink = 11
+setuid = 12
+rename = 13
+exit   = 14
+time   = 15
+intrp  = 16
+chdir  = 17
+chmod  = 18
+chown  = 19
+" 20 removed
+sysloc = 21		" return system addresses
+" 22 removed
+capt   = 23		" capture display?
+rele   = 24		" release display?
+status = 25		" "stat"
+smes   = 27
+rmes   = 28
+fork   = 29
+
+" List of instruction names and machine code values
+" These come from https://raw.githubusercontent.com/simh/
+
+sys    = 0020000		" "cal i" instruction (trap indirect thru 020)
+i      = 0020000		" indirect bit
+
+" memory reference instructions
+dac    = 0040000		" deposit AC
+jms    = 0100000		" jump to subroutine
+dzm    = 0140000		" deposit zero in memory
+lac    = 0200000		" load AC
+xor    = 0240000		" exclusive or
+add    = 0300000		" one's complement add
+tad    = 0340000		" two's complement add
+xct    = 0400000		" execute
+isz    = 0440000		" increment and skip if zero
+and    = 0500000		" AND with contents of Y
+sad    = 0540000		" skip if AC different from content of Y
+jmp    = 0600000		" jump to Y
+
+" Type 177 Extended Arithmetic Element (EAE)
+eae    = 0640000		" base instruction (nop)
+osc    = 0640001		" OR SC into AC
+omq    = 0640002		" OR MQ into AC
+cmq    = 0640004		" Complement MQ
+div    = 0640323		" divide
+norm   = 0640444		" normalize unsigned
+lls    = 0640600		" long left shift
+als    = 0640700		" AC shift
+lrs    = 0640500		" long right shift
+lacs   = 0641001		" load AC with SC
+lacq   = 0641002		" load AC with MQ
+abs    = 0644000		" absolute value
+divs   = 0644323		" divide signed
+
+clq    = 0650000		" clear MQ
+frdiv  = 0650323		" fractional divide
+lmq    = 0652000		" load MQ from AC
+mul    = 0653122		" multiply
+idiv   = 0653323		" integer divide
+idivs  = 0657323		" integer divide signed
+frdivs = 0654323		" fractional divide signed
+muls   = 0657122		" multiply signed
+
+norms  = 0660444		" normalize signed
+gsm    = 0664000		" get sign and magnitude
+lrss   = 0660500		" long right shift signed
+llss   = 0660600		" long left shift signed
+alss   = 0660700		" AC left shift signed
+
+" Operate Instructions
+
+" Group 1 (OPR 1) instructions
+opr    = 0740000		" base operate instruction (nop)
+nop    = 0740000
+cma    = 0740001		" complement accumulator
+cml    = 0740002		" complement link
+oas    = 0740004		" inclusive or accumulator switches
+ral    = 0740010		" rotate (ac link) left
+rar    = 0740020		" rotate (ac link) right
+hlt    = 0740040		" HALT
+xx     = 0740040
+sma    = 0740100		" skip on minus accumulator
+sza    = 0740200		" skip on zero accumulator
+snl    = 0740400		" skip on non-zero link
+
+skp    = 0741000		" unconditional skip
+spa    = 0741100		" skip on positive accumulator
+sna    = 0741200		" skip on negative accumulator
+szl    = 0741400		" skip on zero link
+
+rtl    = 0742010		" rotate two left (ral*2)
+rtr    = 0742020		" rotate two right (rar*2)
+
+cll    = 0744000		" clear link
+stl    = 0744002		" set link
+rcl    = 0744010		" clear link rotate left
+rcr    = 0744020		" clear link rotate right
+
+cla    = 0750000		" clear accumulator
+clc    = 0750001		" clear and complement acc
+las    = 0750004		" load acc from switches
+glk    = 0750010		" get link
+
+" Group 2 operate
+law    = 0760000		" load accumulator with (instruction)