PAYLOAD_EXECUTOR¶

Executes the DRAM payload from memory

Instruction decoder

All instructions are 32-bit. The format of most instructions is the same, except for the LOOP instruction, which has a constant TIMESLICE of 1.

NOOP with a TIMESLICE of 0 is a special case which is interpreted as STOP instruction. When this instruction is encountered execution gets finished immediately.

NOTE: TIMESLICE is the number of cycles the instruction will take. This means that instructions other than NOOP that use TIMESLICE=0 are illegal (although will silently be executed as having TIMESLICE=1).

NOTE2: LOOP instruction will jump COUNT times, meaning that the “code” inside the loop will effectively be executed COUNT+1 times.

Op codes:

Instruction format:

      LSB                       MSB
dfi:  OP_CODE | TIMESLICE | ADDRESS
noop: OP_CODE | TIMESLICE_NOOP
loop: OP_CODE | COUNT     | JUMP
stop: <NOOP>  | 0

Where ADDRESS depends on the DFI command and is one of:

LSB              MSB
RANK | BANK | COLUMN
RANK | BANK | ROW

Register Listing for PAYLOAD_EXECUTOR¶

PAYLOAD_EXECUTOR_START¶

Address: 0xf0004000 + 0x0 = 0xf0004000

Writing to this register initializes payload execution

PAYLOAD_EXECUTOR_STATUS¶

Address: 0xf0004000 + 0x4 = 0xf0004004

Payload executor status register

PAYLOAD_EXECUTOR_READ_COUNT¶

Address: 0xf0004000 + 0x8 = 0xf0004008

Number of data from READ commands that is stored in the scratchpad memory