Constants:
        0       1       2       3       4       7       8       15
        16      23      24      31      32      47      48      255
        256     65535   65536   -1      -2      -3      -4      -8

Misc:
        ip      fp      sp
Global:
        g0      g1      g2      g3      g4
Decoder scratch:
        ds0     ds1     ds2     ds3
System scratch:
        s0      s1      s2      s3
Ingoing parameters:
        i0      i1      i2      i3      i4      i5      i6      ra
Work:
        l0      l1      l2      l3      l4      l5      l6      l7
Outgoing parameters:
        o0      o1      o2      o3      o4      o5      o6      o7




fetch     [src],dst                                        displacement
store     src,[dst]
exchange  src1,[src1]

bop src1,src2,dst,op (op=and2,or2,xor2,copy1)              bitspec

add src1,src2,dst                                          sub

set dst,imm                                                low/high

in [src],dst,w
out src,[dst],w

j [j,jnc,jc,jnz,jncnz,jcnz,jz,jncz,jcz] dst
jr ditto

bmov src,

iiii111111222222          333333
................................
iiii instruction
111111 source reg 1
222222 source reg 2
333333 target


push reg
  store sp,[bp]
  add bp,4,bp

return
  add sp,-4,sp
  fetch ip,[sp]

call addr
  add ip,4,ds0
  store ds0,[sp]
  add sp,4,sp
  j addr

x = y + z
  add bp,_y,ds0
  fetch [ds0],ds0
  set ds1,_z
  fetch [ds1],ds
  add ds0,ds1,ds0
  add bp,_x,ds2
  store ds0,[ds2]

if(x<2) ...
  add bp,_x,ds0
  fetch [ds0],ds1
  add ds1,-2,null
  jc _else
  ...

interlock flags:
  use-flags:
    memory
    io
    reg1,2,3,4
    flags
  modify-flags:
    memory
    io
    reg1,2,3,4
    flags