NXP Semiconductors K32 L2A Series, Справочное руководство, Страница: 236 / 1379

Table 13-3. Cycle definitions of decorated store: logical XOR
Pipeline Stage Cycle
x x+1 x+2
BME AHB_ap Forward addr to memory;
Decode decoration; Convert
master_wt to slave_rd;
Capture address, attributes Recirculate captured addr +
attr to memory as slave_wt <next>
BME AHB_dp <previous> Perform memory read; Form
(rdata ^ wdata) and capture
destination data in register Perform write sending
registered data to memory
13.3.1.4 Decorated store bit field insert (BFI)
This command inserts a bit field contained in the write data operand, defined by LSB
position (b) and the bit field width (w+1), into the memory "container" defined by the
access size associated with the store instruction using an atomic read-modify-write
sequence.
The data size is specified by the write operation and can be byte (8-bit), halfword (16-bit)
or word (32-bit). For BME2, the data field width (addr[22:20]) for bit field inserts and
extracts is limited to an 8-bit or less value, regardless of reference size.
NOTE
The maximum bit field width is 8 bits. The core performs the
required write data lane replication on byte and halfword
transfers.
The BFI operation can be used to insert a single bit into a peripheral. For this case, the w
field is simply set to 0, indicating a bit field width of 1.
iobfib
0 1 - -
mem_addr
iobfih 0 1 -
b
mem_addr
iobfiw
0 1 b b mem_addr
0 1 2 3
4 5 6 7
8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
0
0
0
b
b
b b
b
b b
b
b
w
w
w
w w
w
w w
w
1
1
1 0
0
0
Figure 13-5. Decorated address store: bit field insert
where addr[30:29] =10 for peripheral, addr[28] = 1 signals a BFI operation, addr[27:23]
is "b", the LSB identifier, addr[22:20] is "w", the bit field width minus 1 identifier, and
addr[19:0] specifies the address offset into the peripheral space based at 0x4000_0000.
The "-" indicates an address bit "don't care".
Functional description
K32 L2A Reference Manual, Rev. 2, 01/2020
236 NXP Semiconductors