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74f1d4f47b
Minor adjustments to formatting of the copyright line, but keep dates and holders. "Authors" entries that could be obtained via Git logs were also removed. The license in brw_disasm.c and elk_disasm.c don't match directly any SPDX pattern I could find, so kept as is. Reviewed-by: Ian Romanick <ian.d.romanick@intel.com> Acked-by: Alyssa Rosenzweig <alyssa.rosenzweig@intel.com> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/39503>
58 lines
1.1 KiB
C
58 lines
1.1 KiB
C
/*
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* Copyright © 2014 Intel Corporation
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* SPDX-License-Identifier: MIT
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*/
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#include "brw_reg.h"
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union fu {
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float f;
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unsigned u;
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struct {
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unsigned mantissa:23;
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unsigned exponent:8;
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unsigned sign:1;
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} s;
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};
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int
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brw_float_to_vf(float f)
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{
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union fu fu = { .f = f };
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/* ±0.0f is special cased. */
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if (f == 0.0f)
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return fu.s.sign << 7;
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unsigned mantissa = fu.s.mantissa >> (23 - 4);
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unsigned exponent = fu.s.exponent - (127 - 3);
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unsigned vf = (fu.s.sign << 7) | (exponent << 4) | mantissa;
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/* 0.125 would have had the same representation as 0.0, so reject it. */
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if ((vf & 0x7f) == 0)
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return -1;
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/* Make sure the mantissa fits in 4-bits and the exponent in 3-bits. */
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if (fu.u & 0x7ffff || exponent > 7)
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return -1;
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return vf;
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}
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float
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brw_vf_to_float(unsigned char vf)
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{
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union fu fu;
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/* ±0.0f is special cased. */
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if (vf == 0x00 || vf == 0x80) {
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fu.u = (unsigned)vf << 24;
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return fu.f;
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}
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fu.s.sign = vf >> 7;
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fu.s.exponent = ((vf & 0x70) >> 4) + (127 - 3);
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fu.s.mantissa = (vf & 0xf) << (23 - 4);
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return fu.f;
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}
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