UNIX 6th Ed. - /usr/source/s3/switch.s

   1: / switch -- switch on contents of r0
   2: /
   3: /
   4: / calling sequence --
   5: /
   6: /   jsr r5,switch; swtab
   7: /
   8: / r0 is looked up in swtab and if found
   9: / control is returned to the corresponding place
  10: / if r0 is not found, the next inline instruction is
  11: / executed
  12: /
  13: / swtab format --
  14: /
  15: / swtab:
  16: /    val1; ret1
  17: /   val2; ret2
  18: /   ...
  19: /   valn; retn
  20: /   ..; 0
  21: /
  22: 
  23:         .globl  switch
  24: switch:
  25:         mov     r1,-(sp)
  26:         mov     (r5)+,r1
  27: 1:
  28:         cmp     r0,(r1)+
  29:         beq     1f
  30:         tst     (r1)+
  31:         bne     1b
  32: 2:
  33:         mov     (sp)+,r1
  34:         rts     r5
  35: 1:
  36:         mov     (r1)+,r1
  37:         beq     2b
  38:         mov     r1,r5
  39:         br      2b

Defined functions