Commit 571cbd05 authored by Juan Suárez Romero's avatar Juan Suárez Romero Committed by Francisco Jerez

i965/fs: fix dst stride in IVB/BYT type conversions

When converting a DF to 32-bit conversions, we set dst stride to 2,
to fulfill alignment restrictions because the upper Dword of every
Qword will be written with undefined value.

But in IVB/BYT, this is not necessary, as each DF conversion already
writes 2, the first one the real value, and the second one a 0.
That is, IVB/BYT already set stride = 2 implicitly, so we must set it to
1 explicitly to avoid ending up with stride = 4.

v2:
- Fix typo (Matt)

v3:
- Fix stride in the destination's brw_reg, don't modity IR (Curro)

v4:
- Remove 'is_dst' argument of brw_reg_from_fs_reg() (Curro)
- Fix comment (Curro).
- Relax hstride assert (Curro)
Signed-off-by: Juan Suárez Romero's avatarJuan A. Suarez Romero <jasuarez@igalia.com>
Signed-off-by: Samuel Iglesias Gonsálvez's avatarSamuel Iglesias Gonsálvez <siglesias@igalia.com>
[ Francisco Jerez: Minor spelling fixes. ]
Reviewed-by: Francisco Jerez's avatarFrancisco Jerez <currojerez@riseup.net>
parent af6fc3a8
......@@ -93,33 +93,47 @@ brw_reg_from_fs_reg(const struct gen_device_info *devinfo, fs_inst *inst,
const unsigned width = MIN2(reg_width, phys_width);
brw_reg = brw_vecn_reg(width, brw_file_from_reg(reg), reg->nr, 0);
brw_reg = stride(brw_reg, width * reg->stride, width, reg->stride);
/* From the IvyBridge PRM (EU Changes by Processor Generation, page 13):
* "Each DF (Double Float) operand uses an element size of 4 rather
* than 8 and all regioning parameters are twice what the values
* would be based on the true element size: ExecSize, Width,
* HorzStride, and VertStride. Each DF operand uses a pair of
* channels and all masking and swizzing should be adjusted
* appropriately."
*
* From the IvyBridge PRM (Special Requirements for Handling Double
* Precision Data Types, page 71):
* "In Align1 mode, all regioning parameters like stride, execution
* size, and width must use the syntax of a pair of packed
* floats. The offsets for these data types must be 64-bit
* aligned. The execution size and regioning parameters are in terms
* of floats."
*
* Summarized: when handling DF-typed arguments, ExecSize,
* VertStride, and Width must be doubled.
*
* It applies to BayTrail too.
*/
if (devinfo->gen == 7 && !devinfo->is_haswell &&
type_sz(reg->type) == 8) {
brw_reg.width++;
if (brw_reg.vstride > 0)
brw_reg.vstride++;
assert(brw_reg.hstride == BRW_HORIZONTAL_STRIDE_1);
if (devinfo->gen == 7 && !devinfo->is_haswell) {
/* From the IvyBridge PRM (EU Changes by Processor Generation, page 13):
* "Each DF (Double Float) operand uses an element size of 4 rather
* than 8 and all regioning parameters are twice what the values
* would be based on the true element size: ExecSize, Width,
* HorzStride, and VertStride. Each DF operand uses a pair of
* channels and all masking and swizzing should be adjusted
* appropriately."
*
* From the IvyBridge PRM (Special Requirements for Handling Double
* Precision Data Types, page 71):
* "In Align1 mode, all regioning parameters like stride, execution
* size, and width must use the syntax of a pair of packed
* floats. The offsets for these data types must be 64-bit
* aligned. The execution size and regioning parameters are in terms
* of floats."
*
* Summarized: when handling DF-typed arguments, ExecSize,
* VertStride, and Width must be doubled.
*
* It applies to BayTrail too.
*/
if (type_sz(reg->type) == 8) {
brw_reg.width++;
if (brw_reg.vstride > 0)
brw_reg.vstride++;
assert(brw_reg.hstride == BRW_HORIZONTAL_STRIDE_1);
}
/* When converting from DF->F, we set the destination stride to 2
* because each d2f conversion implicitly writes 2 floats, being
* the first one the converted value. IVB/BYT actually writes two
* F components per SIMD channel, and every other component is
* filled with garbage.
*/
if (reg == &inst->dst && get_exec_type_size(inst) == 8 &&
type_sz(inst->dst.type) < 8) {
assert(brw_reg.hstride > BRW_HORIZONTAL_STRIDE_1);
brw_reg.hstride--;
}
}
}
......
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