Changes between Version 20 and Version 21 of GcnInstrsVop1


Ignore:
Timestamp:
05/22/16 12:01:04 (8 years ago)
Author:
trac
Comment:

--

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  • GcnInstrsVop1

    v20 v21  
    13171317else
    13181318    VDST = 0.0</code></p>
     1319<h3>V_EXP_LEGACY_F32</h3>
     1320<p>Opcode VOP1: 70 (0x46) for GCN 1.1; 75 (0x4b) for GCN 1.2<br />
     1321Opcode VOP3A: 454 (0x1c6) for GCN 1.1; 395 (0x18b) for GCN 1.2<br />
     1322Syntax: V_EXP_LEGACY_F32 VDST, SRC0<br />
     1323Description: Approximate power of two from FP value SRC0 and store it to VDST. Instruction
     1324for values smaller than -126.0 always returns 0 regardless floatmode in MODE register.
     1325For some cases this instructions returns slightly less accurate result than V_EXP_F32.<br />
     1326Operation:<br />
     1327<code>if (ASFLOAT(SRC0)&gt;=-126.0)
     1328    VDST = APPROX_POW2(ASFLOAT(SRC0))
     1329else
     1330    VDST = 0.0</code></p>
    13191331<h4>V_FFBH_U32</h4>
    13201332<p>Opcode VOP1: 57 (0x39) for GCN 1.0/1.1; 45 (0x2d) for GCN 1.2<br />
     
    14821494else
    14831495    VDST = APPROX_LOG2(F)</code></p>
     1496<h4>V_LOG_LEGACY_F32</h4>
     1497<p>Opcode VOP1: 69 (0x45) for GCN 1.1; 76 (0x4c) for GCN 1.2<br />
     1498Opcode VOP3A: 453 (0x1c5) for GCN 1.1; 396 (0x18c) for GCN 1.2<br />
     1499Syntax: V_LOG_LEGACY_F32 VDST, SRC0<br />
     1500Description: Approximate logarithm of base 2 from floating point value SRC0, and store result
     1501to VDST. If SRC0 is negative then store -NaN to VDST.
     1502This instruction doesn't handle denormalized values regardless FLOAT MODE register setup.
     1503This instruction returns slightly different results than V_LOG_F32.<br />
     1504Operation:<br />
     1505<code>FLOAT F = ASFLOAT(SRC0)
     1506if (F==1.0)
     1507    VDST = 0.0f
     1508if (F&lt;0.0)
     1509    VDST = -NaN
     1510else
     1511    VDST = APPROX_LOG2(F)</code></p>
    14841512<h4>V_MOV_B32</h4>
    14851513<p>Opcode VOP1: 1 (0x1)<br />