openpower/isa/fixedtrap.mdwn

   1 <!-- This defines instructions described in PowerISA Version 3.0 B Book 1 -->
   2
   3 <!-- Section 3.3.11 Fixed-Point Trap Instructions pages 89 - 91 -->
   4
   5 <!-- The Trap instructions are provided to test for a specified set of conditions. -->
   6 <!-- If any of the conditions tested by a Trap instruction are met, the system trap -->
   7 <!-- handler is invoked. If none of the tested conditions are met, instruction -->
   8 <!-- execution continues normally. -->
   9
  10 # Trap Word Immediate
  11
  12 D-Form
  13
  14 * twi TO,RA,SI
  15
  16 Pseudo-code:
  17
  18     a <- EXTS((RA)[XLEN/2:XLEN-1])
  19     if (a < EXTS(SI)) & TO[0]  then TRAP
  20     if (a > EXTS(SI)) & TO[1]  then TRAP
  21     if (a = EXTS(SI)) & TO[2]  then TRAP
  22     if (a <u EXTS(SI)) & TO[3] then TRAP
  23     if (a >u EXTS(SI)) & TO[4] then TRAP
  24
  25 Special Registers Altered:
  26
  27     None
  28
  29 # Trap Word
  30
  31 X-Form
  32
  33 * tw TO,RA,RB
  34
  35 Pseudo-code:
  36
  37     a <- EXTS((RA)[XLEN/2:XLEN-1])
  38     b <- EXTS((RB)[XLEN/2:XLEN-1])
  39     if (a < b) & TO[0] then TRAP
  40     if (a > b) & TO[1] then TRAP
  41     if (a = b) & TO[2] then TRAP
  42     if (a <u b) & TO[3] then TRAP
  43     if (a >u b) & TO[4] then TRAP
  44
  45 Special Registers Altered:
  46
  47     None
  48
  49 # Trap Doubleword Immediate
  50
  51 D-Form
  52
  53 * tdi TO,RA,SI
  54
  55 Pseudo-code:
  56
  57     a <- (RA)
  58     b <- EXTS(SI)
  59     if (a < b) & TO[0] then TRAP
  60     if (a > b) & TO[1] then TRAP
  61     if (a = b) & TO[2] then TRAP
  62     if (a <u  b) & TO[3] then TRAP
  63     if (a >u  b) & TO[4]  then TRAP
  64
  65 Special Registers Altered:
  66
  67     None
  68
  69 # Trap Doubleword
  70
  71 X-Form
  72
  73 * td TO,RA,RB
  74
  75 Pseudo-code:
  76
  77     a <- (RA)
  78     b <- (RB)
  79     if (a < b) & TO[0] then TRAP
  80     if (a > b) & TO[1] then TRAP
  81     if (a = b) & TO[2] then TRAP
  82     if (a <u b) & TO[3] then TRAP
  83     if (a >u b) & TO[4]  then TRAP
  84
  85 Special Registers Altered:
  86
  87     None
  88
  89 # Integer Select
  90
  91 A-Form
  92
  93 * isel RT,RA,RB,BC
  94
  95 Pseudo-code:
  96
  97     if CR[BC+32]=1 then RT <- (RA|0)
  98     else                RT <- (RB)
  99
 100 Special Registers Altered:
 101
 102     None
 103
 104 <!-- Checked March 2021 -->