KonstantinSeurer
/
mesa
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

pan/bi: Add dummy carry/borrow argument for iadd/isub 

On FMA, a carry/borrow is required for iaddc/isubb (whereas the ADD
counterparts don't support carrying/borrowing). The trick is to model
this with an extra dummy (ZERO) argument which is free to encode on FMA,
and in the scheduler, "demote" to the non-carried versions if we want to
schedule to ADD.

Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6749>
This commit is contained in:
Alyssa Rosenzweig 2020-07-31 16:47:05 -04:00 committed by Marge Bot
parent 42ec4aa478
commit 33710ff895
2 changed files with 5 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
src/panfrost/bifrost/bifrost_compile.c
View File

@ -805,9 +805,13 @@ emit_alu(bi_context *ctx, nir_alu_instr *instr)
break;
case nir_op_iadd:
alu.op.imath = BI_IMATH_ADD;
/* Carry */
alu.src[2] = BIR_INDEX_ZERO;
break;
case nir_op_isub:
alu.op.imath = BI_IMATH_SUB;
/* Borrow */
alu.src[2] = BIR_INDEX_ZERO;
break;
case nir_op_iabs:
alu.op.special = BI_SPECIAL_IABS;

1
src/panfrost/bifrost/test/bi_test_pack.c
View File

@ -557,6 +557,7 @@ bit_imath_helper(struct panfrost_device *dev, uint32_t *input, unsigned size, en
{
bi_instruction ins = bit_ins(BI_IMATH, 2, nir_type_uint, size);
bit_swizzle_identity(&ins, 2, size);
ins.src[2] = BIR_INDEX_ZERO; /* carry/borrow for FMA */
for (unsigned op = BI_IMATH_ADD; op <= BI_IMATH_SUB; ++op) {
ins.op.imath = op;