PTX ISA v9.2

9.7.14.5. Matrix Fragments for mma.m8n8k128

A warp executing mma.m8n8k128 will compute an MMA operation of shape .m8n8k128.

Elements of the matrix are distributed across the threads in a warp so each thread of the warp holds a fragment of the matrix.

Multiplicand A:

.atype Fragment Elements (low to high)
.b1 A vector expression containing a single .b32 register, containing thirty two .b1 elements from the matrix A. a0, a1, … a30, a31

The layout of the fragments held by different threads is shown in Figure 62.

MMA .m8n8k128 fragment layout for matrix A with .b1 type

Figure 62 MMA .m8n8k128 fragment layout for matrix A with .b1 type.

The row and column of a matrix fragment can be computed as:

groupID           = %laneid >> 2
threadID_in_group = %laneid % 4

row =  groupID

col =  (threadID_in_group * 32) + i       for ai where i = {0,..,31}

Multiplicand B:

.btype Fragment Elements (low to high)
.b1 A vector expression containing a single .b32 register, containing thirty two .b1 elements from the matrix B. b0, b1, …, b30, b31

The layout of the fragments held by different threads is shown in Figure 63.

MMA .m8n8k128 fragment layout for matrix B with .b1 type

Figure 63 MMA .m8n8k128 fragment layout for matrix B with .b1 type.

The row and column of a matrix fragment can be computed as:

groupID           = %laneid >> 2
threadID_in_group = %laneid % 4

row = (threadID_in_group * 32) + i         for bi where i = {0,..,31}

col = groupID

Accumulators (C or D):

.ctype / .dtype Fragment Elements (low to high)
.s32 A vector expression containing two .s32 registers, containing two .s32 elements from the matrix C (or D). c0, c1

The layout of the fragments held by different threads is shown in Figure 64.

MMA .m8n8k128 fragment layout for accumulator matrix C/D with .s32 type

Figure 64 MMA .m8n8k128 fragment layout for accumulator matrix C/D with .s32 type

The row and column of a matrix fragment can be computed as:

groupID = %laneid >> 2
threadID_in_group = %laneid % 4

row =      groupID

col =  (threadID_in_group * 2) + i    for ci where i = {0, 1}
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