ecp5: add support for both 1364.1 and LSE RAM/ROM attributes.

This commit tries to carefully follow the documented behavior of LSE
and Synplify. It will use `syn_ramstyle` attribute if there are any
write ports, and `syn_romstyle` attribute otherwise.
  * LSE supports both `syn_ramstyle` and `syn_romstyle`.
  * Synplify only supports `syn_ramstyle`, with same values as LSE.
  * Synplify also supports `syn_rw_conflict_logic`, which is not
    documented as supported for LSE.

Limitations of the Yosys implementation:
  * LSE/Synplify support `syn_ramstyle="block_ram,no_rw_check"`
    syntax to turn off insertion of transparency logic. There is
    currently no way to support multiple valued attributes in
    memory_bram. It is also not clear if that is a good idea, since
    it can cause sim/synth mismatches.
  * LSE/Synplify/1364.1 support block ROM inference from full case
    statements. Yosys does not currently perform this transformation.
  * LSE/Synplify propagate `syn_ramstyle`/`syn_romstyle` attributes
    from the module to the inner memories. There is currently no way
    to do this in Yosys (attrmvcp only works on cells and wires).

diff --git a/techlibs/ecp5/brams.txt b/techlibs/ecp5/brams.txt
index 777ccaa2eba1efaf77902acef1077a1d05b2016b..d34d9ec07463be69b32015ac4d1006b532af11f2 100644 (file)
--- a/techlibs/ecp5/brams.txt
+++ b/techlibs/ecp5/brams.txt
@@ -37,7 +37,17 @@ bram $__ECP5_DP16KD
   clkpol 2 3
 endbram
 
+# The syn_* attributes are described in:
+# https://www.latticesemi.com/-/media/LatticeSemi/Documents/Tutorials/AK/LatticeDiamondTutorial311.ashx
+attr_icase 1
+
 match $__ECP5_PDPW16KD
+  # implicitly requested RAM or ROM
+  attribute !syn_ramstyle syn_ramstyle=auto
+  attribute !syn_romstyle syn_romstyle=auto
+  attribute !ram_block
+  attribute !rom_block
+  attribute !logic_block
   min bits 2048
   min efficiency 5
   shuffle_enable A
@@ -45,8 +55,60 @@ match $__ECP5_PDPW16KD
   or_next_if_better
 endmatch
 
+match $__ECP5_PDPW16KD
+  # explicitly requested RAM
+  attribute syn_ramstyle=block_ram ram_block
+  attribute !syn_romstyle
+  attribute !rom_block
+  attribute !logic_block
+  min wports 1
+  shuffle_enable A
+  make_transp
+  or_next_if_better
+endmatch
+
+match $__ECP5_PDPW16KD
+  # explicitly requested ROM
+  attribute syn_romstyle=ebr rom_block
+  attribute !syn_ramstyle
+  attribute !ram_block
+  attribute !logic_block
+  max wports 0
+  shuffle_enable A
+  make_transp
+  or_next_if_better
+endmatch
+
 match $__ECP5_DP16KD
+  # implicitly requested RAM or ROM
+  attribute !syn_ramstyle syn_ramstyle=auto
+  attribute !syn_romstyle syn_romstyle=auto
+  attribute !ram_block
+  attribute !rom_block
+  attribute !logic_block
   min bits 2048
   min efficiency 5
   shuffle_enable A
+  or_next_if_better
+endmatch
+
+match $__ECP5_DP16KD
+  # explicitly requested RAM
+  attribute syn_ramstyle=block_ram ram_block
+  attribute !syn_romstyle
+  attribute !rom_block
+  attribute !logic_block
+  min wports 1
+  shuffle_enable A
+  or_next_if_better
+endmatch
+
+match $__ECP5_DP16KD
+  # explicitly requested ROM
+  attribute syn_romstyle=ebr rom_block
+  attribute !syn_ramstyle
+  attribute !ram_block
+  attribute !logic_block
+  max wports 0
+  shuffle_enable A
 endmatch

diff --git a/techlibs/ecp5/lutrams.txt b/techlibs/ecp5/lutrams.txt
index b943574290ed90666d76d94f145b1b60e733dad6..9e6a23eba7e981a52fa4b816d36a294985c2e87e 100644 (file)
--- a/techlibs/ecp5/lutrams.txt
+++ b/techlibs/ecp5/lutrams.txt
@@ -11,7 +11,16 @@ bram $__TRELLIS_DPR16X4
   clkpol 0 2
 endbram
 
+# The syn_* attributes are described in:
+# https://www.latticesemi.com/-/media/LatticeSemi/Documents/Tutorials/AK/LatticeDiamondTutorial311.ashx
+attr_icase 1
+
 match $__TRELLIS_DPR16X4
+       attribute !syn_ramstyle syn_ramstyle=auto syn_ramstyle=distributed
+       attribute !syn_romstyle syn_romstyle=auto
+       attribute !ram_block
+       attribute !rom_block
+       attribute !logic_block
   make_outreg
   min wports 1
 endmatch

diff --git a/tests/arch/common/blockrom.v b/tests/arch/common/blockrom.v
index 6f6c9d9464e1211b47085df90537bc447701b697..93f5c9ddffaae58ecf311088a04462d780ffba5e 100644 (file)
--- a/tests/arch/common/blockrom.v
+++ b/tests/arch/common/blockrom.v
@@ -10,16 +10,16 @@ module sync_rom #(parameter DATA_WIDTH=8, ADDRESS_WIDTH=10)
        reg [WORD:0] data_out_r;
        reg [WORD:0] memory [0:DEPTH];
 
-       integer i,j = 16'hACE1;
+       integer i,j = 64'hF4B1CA8127865242;
        initial
                for (i = 0; i <= DEPTH; i++) begin
                        // In case this ROM will be implemented in fabric: fill the memory with some data
                        // uncorrelated with the address, or Yosys might see through the ruse and e.g. not
                        // emit any LUTs at all for `memory[i] = i;`, just a latch.
-                       memory[i] = j;
-                       j = j ^ (j >> 7);
-                       j = j ^ (j << 9);
-                       j = j ^ (j >> 13);
+                       memory[i] = j * 64'h2545F4914F6CDD1D;
+                       j = j ^ (j >> 12);
+                       j = j ^ (j << 25);
+                       j = j ^ (j >> 27);
                end
 
        always @(posedge clk) begin

diff --git a/tests/arch/ecp5/memories.ys b/tests/arch/ecp5/memories.ys
new file mode 100644 (file)
index 0000000..64005ba
--- /dev/null
+++ b/tests/arch/ecp5/memories.ys
@@ -0,0 +1,284 @@
+# ================================ RAM ================================
+# RAM bits <= 18K; Data width <= 36; Address width <= 9: -> PDPW16KD
+
+design -reset; read_verilog ../common/blockram.v
+chparam -set ADDRESS_WIDTH 9 -set DATA_WIDTH 36 sync_ram_sdp
+synth_ecp5 -top sync_ram_sdp; cd sync_ram_sdp
+select -assert-count 1 t:PDPW16KD
+
+## With parameters
+
+design -reset; read_verilog ../common/blockram.v
+chparam -set ADDRESS_WIDTH 2 -set DATA_WIDTH 36 sync_ram_sdp
+synth_ecp5 -top sync_ram_sdp; cd sync_ram_sdp
+select -assert-count 0 t:PDPW16KD # too inefficient
+select -assert-count 9 t:TRELLIS_DPR16X4
+
+design -reset; read_verilog ../common/blockram.v
+chparam -set ADDRESS_WIDTH 2 -set DATA_WIDTH 36 sync_ram_sdp
+setattr -set syn_ramstyle "block_ram" m:memory
+synth_ecp5 -top sync_ram_sdp; cd sync_ram_sdp
+select -assert-count 1 t:PDPW16KD
+
+design -reset; read_verilog ../common/blockram.v
+chparam -set ADDRESS_WIDTH 2 -set DATA_WIDTH 36 sync_ram_sdp
+setattr -set syn_ramstyle "Block_RAM" m:memory
+synth_ecp5 -top sync_ram_sdp; cd sync_ram_sdp
+select -assert-count 1 t:PDPW16KD # any case works
+
+design -reset; read_verilog ../common/blockram.v
+chparam -set ADDRESS_WIDTH 2 -set DATA_WIDTH 36 sync_ram_sdp
+setattr -set ram_block 1 m:memory
+synth_ecp5 -top sync_ram_sdp; cd sync_ram_sdp
+select -assert-count 1 t:PDPW16KD
+
+design -reset; read_verilog ../common/blockram.v
+chparam -set ADDRESS_WIDTH 2 -set DATA_WIDTH 36 sync_ram_sdp
+setattr -set syn_ramstyle "registers" m:memory
+synth_ecp5 -top sync_ram_sdp; cd sync_ram_sdp
+select -assert-count 0 t:PDPW16KD # requested FFRAM explicitly
+select -assert-count 180 t:TRELLIS_FF
+
+design -reset; read_verilog ../common/blockram.v
+chparam -set ADDRESS_WIDTH 2 -set DATA_WIDTH 36 sync_ram_sdp
+setattr -set logic_block 1 m:memory
+synth_ecp5 -top sync_ram_sdp; cd sync_ram_sdp
+select -assert-count 0 t:PDPW16KD # requested FFRAM explicitly
+select -assert-count 180 t:TRELLIS_FF
+
+design -reset; read_verilog ../common/blockram.v
+chparam -set ADDRESS_WIDTH 2 -set DATA_WIDTH 36 sync_ram_sdp
+setattr -set syn_romstyle "ebr" m:memory
+synth_ecp5 -top sync_ram_sdp; cd sync_ram_sdp
+select -assert-count 0 t:PDPW16KD # requested BROM but this is a RAM
+select -assert-count 180 t:TRELLIS_FF
+
+design -reset; read_verilog ../common/blockram.v
+chparam -set ADDRESS_WIDTH 2 -set DATA_WIDTH 36 sync_ram_sdp
+setattr -set rom_block 1 m:memory
+synth_ecp5 -top sync_ram_sdp; cd sync_ram_sdp
+select -assert-count 0 t:PDPW16KD # requested BROM but this is a RAM
+select -assert-count 180 t:TRELLIS_FF
+
+# RAM bits <= 18K; Data width <= 18; Address width <= 10: -> DP16KD
+
+design -reset; read_verilog ../common/blockram.v
+chparam -set ADDRESS_WIDTH 10 -set DATA_WIDTH 18 sync_ram_sdp
+synth_ecp5 -top sync_ram_sdp; cd sync_ram_sdp
+select -assert-count 1 t:DP16KD
+
+design -reset; read_verilog ../common/blockram.v
+chparam -set ADDRESS_WIDTH 11 -set DATA_WIDTH 9 sync_ram_sdp
+synth_ecp5 -top sync_ram_sdp; cd sync_ram_sdp
+select -assert-count 1 t:DP16KD
+
+design -reset; read_verilog ../common/blockram.v
+chparam -set ADDRESS_WIDTH 12 -set DATA_WIDTH 4 sync_ram_sdp
+synth_ecp5 -top sync_ram_sdp; cd sync_ram_sdp
+select -assert-count 1 t:DP16KD
+
+design -reset; read_verilog ../common/blockram.v
+chparam -set ADDRESS_WIDTH 13 -set DATA_WIDTH 2 sync_ram_sdp
+synth_ecp5 -top sync_ram_sdp; cd sync_ram_sdp
+select -assert-count 1 t:DP16KD
+
+design -reset; read_verilog ../common/blockram.v
+chparam -set ADDRESS_WIDTH 14 -set DATA_WIDTH 1 sync_ram_sdp
+synth_ecp5 -top sync_ram_sdp; cd sync_ram_sdp
+select -assert-count 1 t:DP16KD
+
+## With parameters
+
+design -reset; read_verilog ../common/blockram.v
+chparam -set ADDRESS_WIDTH 2 -set DATA_WIDTH 18 sync_ram_sdp
+synth_ecp5 -top sync_ram_sdp; cd sync_ram_sdp
+select -assert-count 0 t:DP16KD # too inefficient
+select -assert-count 5 t:TRELLIS_DPR16X4
+
+design -reset; read_verilog ../common/blockram.v
+chparam -set ADDRESS_WIDTH 2 -set DATA_WIDTH 18 sync_ram_sdp
+setattr -set syn_ramstyle "block_ram" m:memory
+synth_ecp5 -top sync_ram_sdp; cd sync_ram_sdp
+select -assert-count 1 t:DP16KD
+
+design -reset; read_verilog ../common/blockram.v
+chparam -set ADDRESS_WIDTH 2 -set DATA_WIDTH 18 sync_ram_sdp
+setattr -set syn_ramstyle "Block_RAM" m:memory
+synth_ecp5 -top sync_ram_sdp; cd sync_ram_sdp
+select -assert-count 1 t:DP16KD # any case works
+
+design -reset; read_verilog ../common/blockram.v
+chparam -set ADDRESS_WIDTH 2 -set DATA_WIDTH 18 sync_ram_sdp
+setattr -set ram_block 1 m:memory
+synth_ecp5 -top sync_ram_sdp; cd sync_ram_sdp
+select -assert-count 1 t:DP16KD
+
+design -reset; read_verilog ../common/blockram.v
+chparam -set ADDRESS_WIDTH 2 -set DATA_WIDTH 18 sync_ram_sdp
+setattr -set syn_ramstyle "registers" m:memory
+synth_ecp5 -top sync_ram_sdp; cd sync_ram_sdp
+select -assert-count 0 t:DP16KD # requested FFRAM explicitly
+select -assert-count 90 t:TRELLIS_FF
+
+design -reset; read_verilog ../common/blockram.v
+chparam -set ADDRESS_WIDTH 2 -set DATA_WIDTH 18 sync_ram_sdp
+setattr -set logic_block 1 m:memory
+synth_ecp5 -top sync_ram_sdp; cd sync_ram_sdp
+select -assert-count 0 t:DP16KD # requested FFRAM explicitly
+select -assert-count 90 t:TRELLIS_FF
+
+design -reset; read_verilog ../common/blockram.v
+chparam -set ADDRESS_WIDTH 2 -set DATA_WIDTH 18 sync_ram_sdp
+setattr -set syn_romstyle "ebr" m:memory
+synth_ecp5 -top sync_ram_sdp; cd sync_ram_sdp
+select -assert-count 0 t:DP16KD # requested BROM but this is a RAM
+select -assert-count 90 t:TRELLIS_FF
+
+design -reset; read_verilog ../common/blockram.v
+chparam -set ADDRESS_WIDTH 2 -set DATA_WIDTH 18 sync_ram_sdp
+setattr -set rom_block 1 m:memory
+synth_ecp5 -top sync_ram_sdp; cd sync_ram_sdp
+select -assert-count 0 t:DP16KD # requested BROM but this is a RAM
+select -assert-count 90 t:TRELLIS_FF
+
+# RAM bits <= 64; Data width <= 4; Address width <= 4: -> DPR16X4
+
+design -reset; read_verilog ../common/blockram.v
+chparam -set ADDRESS_WIDTH 4 -set DATA_WIDTH 4 sync_ram_sdp
+synth_ecp5 -top sync_ram_sdp; cd sync_ram_sdp
+select -assert-count 1 t:TRELLIS_DPR16X4
+
+## With parameters
+
+design -reset; read_verilog ../common/blockram.v
+chparam -set ADDRESS_WIDTH 4 -set DATA_WIDTH 4 sync_ram_sdp
+setattr -set syn_ramstyle "distributed" m:memory
+synth_ecp5 -top sync_ram_sdp; cd sync_ram_sdp
+select -assert-count 1 t:TRELLIS_DPR16X4
+
+design -reset; read_verilog ../common/blockram.v
+chparam -set ADDRESS_WIDTH 4 -set DATA_WIDTH 4 sync_ram_sdp
+setattr -set syn_ramstyle "registers" m:memory
+synth_ecp5 -top sync_ram_sdp; cd sync_ram_sdp
+select -assert-count 0 t:TRELLIS_DPR16X4 # requested FFRAM explicitly
+select -assert-count 68 t:TRELLIS_FF
+
+design -reset; read_verilog ../common/blockram.v
+chparam -set ADDRESS_WIDTH 4 -set DATA_WIDTH 4 sync_ram_sdp
+setattr -set logic_block 1 m:memory
+synth_ecp5 -top sync_ram_sdp; cd sync_ram_sdp
+select -assert-count 0 t:TRELLIS_DPR16X4 # requested FFRAM explicitly
+select -assert-count 68 t:TRELLIS_FF
+
+# ================================ ROM ================================
+# ROM bits <= 18K; Data width <= 36; Address width <= 9: -> PDPW16KD
+
+design -reset; read_verilog ../common/blockrom.v
+chparam -set ADDRESS_WIDTH 9 -set DATA_WIDTH 36 sync_rom
+synth_ecp5 -top sync_rom; cd sync_rom
+select -assert-count 1 t:PDPW16KD
+
+## With parameters
+
+design -reset; read_verilog ../common/blockrom.v
+chparam -set ADDRESS_WIDTH 3 -set DATA_WIDTH 36 sync_rom
+write_ilang
+synth_ecp5 -top sync_rom; cd sync_rom
+select -assert-count 0 t:PDPW16KD # too inefficient
+select -assert-min 18 t:LUT4
+
+design -reset; read_verilog ../common/blockrom.v
+chparam -set ADDRESS_WIDTH 2 -set DATA_WIDTH 36 sync_rom
+setattr -set syn_romstyle "ebr" m:memory
+synth_ecp5 -top sync_rom; cd sync_rom
+select -assert-count 1 t:PDPW16KD
+
+design -reset; read_verilog ../common/blockrom.v
+chparam -set ADDRESS_WIDTH 2 -set DATA_WIDTH 36 sync_rom
+setattr -set rom_block 1 m:memory
+synth_ecp5 -top sync_rom; cd sync_rom
+select -assert-count 1 t:PDPW16KD
+
+design -reset; read_verilog ../common/blockrom.v
+chparam -set ADDRESS_WIDTH 3 -set DATA_WIDTH 36 sync_rom
+setattr -set syn_romstyle "logic" m:memory
+synth_ecp5 -top sync_rom; cd sync_rom
+select -assert-count 0 t:PDPW16KD # requested LUTROM explicitly
+select -assert-min 18 t:LUT4
+
+design -reset; read_verilog ../common/blockrom.v
+chparam -set ADDRESS_WIDTH 3 -set DATA_WIDTH 36 sync_rom
+setattr -set logic_block 1 m:memory
+synth_ecp5 -top sync_rom; cd sync_rom
+select -assert-count 0 t:PDPW16KD # requested LUTROM explicitly
+select -assert-min 18 t:LUT4
+
+design -reset; read_verilog ../common/blockrom.v
+chparam -set ADDRESS_WIDTH 2 -set DATA_WIDTH 36 sync_rom
+setattr -set syn_ramstyle "block_ram" m:memory
+synth_ecp5 -top sync_rom; cd sync_rom
+select -assert-count 0 t:PDPW16KD # requested BRAM but this is a ROM
+select -assert-min 18 t:LUT4
+
+design -reset; read_verilog ../common/blockrom.v
+chparam -set ADDRESS_WIDTH 2 -set DATA_WIDTH 36 sync_rom
+setattr -set ram_block 1 m:memory
+synth_ecp5 -top sync_rom; cd sync_rom
+select -assert-count 0 t:PDPW16KD # requested BRAM but this is a ROM
+select -assert-min 18 t:LUT4
+
+# ROM bits <= 18K; Data width <= 18; Address width <= 10: -> DP16KD
+
+design -reset; read_verilog ../common/blockrom.v
+chparam -set ADDRESS_WIDTH 10 -set DATA_WIDTH 18 sync_rom
+synth_ecp5 -top sync_rom; cd sync_rom
+select -assert-count 1 t:DP16KD
+
+## With parameters
+
+design -reset; read_verilog ../common/blockrom.v
+chparam -set ADDRESS_WIDTH 3 -set DATA_WIDTH 18 sync_rom
+write_ilang
+synth_ecp5 -top sync_rom; cd sync_rom
+select -assert-count 0 t:DP16KD # too inefficient
+select -assert-min 9 t:LUT4
+
+design -reset; read_verilog ../common/blockrom.v
+chparam -set ADDRESS_WIDTH 2 -set DATA_WIDTH 18 sync_rom
+setattr -set syn_romstyle "ebr" m:memory
+synth_ecp5 -top sync_rom; cd sync_rom
+select -assert-count 1 t:DP16KD
+
+design -reset; read_verilog ../common/blockrom.v
+chparam -set ADDRESS_WIDTH 2 -set DATA_WIDTH 18 sync_rom
+setattr -set rom_block 1 m:memory
+synth_ecp5 -top sync_rom; cd sync_rom
+select -assert-count 1 t:DP16KD
+
+design -reset; read_verilog ../common/blockrom.v
+chparam -set ADDRESS_WIDTH 3 -set DATA_WIDTH 18 sync_rom
+setattr -set syn_romstyle "logic" m:memory
+synth_ecp5 -top sync_rom; cd sync_rom
+select -assert-count 0 t:DP16KD # requested LUTROM explicitly
+select -assert-min 9 t:LUT4
+
+design -reset; read_verilog ../common/blockrom.v
+chparam -set ADDRESS_WIDTH 3 -set DATA_WIDTH 18 sync_rom
+setattr -set logic_block 1 m:memory
+synth_ecp5 -top sync_rom; cd sync_rom
+select -assert-count 0 t:DP16KD # requested LUTROM explicitly
+select -assert-min 9 t:LUT4
+
+design -reset; read_verilog ../common/blockrom.v
+chparam -set ADDRESS_WIDTH 2 -set DATA_WIDTH 18 sync_rom
+setattr -set syn_ramstyle "block_ram" m:memory
+synth_ecp5 -top sync_rom; cd sync_rom
+select -assert-count 0 t:DP16KD # requested BRAM but this is a ROM
+select -assert-min 9 t:LUT4
+
+design -reset; read_verilog ../common/blockrom.v
+chparam -set ADDRESS_WIDTH 2 -set DATA_WIDTH 18 sync_rom
+setattr -set ram_block 1 m:memory
+synth_ecp5 -top sync_rom; cd sync_rom
+select -assert-count 0 t:DP16KD # requested BRAM but this is a ROM
+select -assert-min 9 t:LUT4

diff --git a/tests/arch/ice40/memories.ys b/tests/arch/ice40/memories.ys
index 43bcf2452cc1469efc1446240abcce6793eb0028..86a60b2582050692aceaf39a37f735f8d0cfe6dd 100644 (file)
--- a/tests/arch/ice40/memories.ys
+++ b/tests/arch/ice40/memories.ys
@@ -1,3 +1,4 @@
+# ================================ RAM ================================
 # RAM bits <= 4K; Data width <= 16; Address width <= 11: -> SB_RAM40_4K
 
 design -reset; read_verilog ../common/blockram.v
@@ -46,6 +47,13 @@ setattr -set ram_block 1 m:memory
 synth_ice40 -top sync_ram_sdp; cd sync_ram_sdp
 select -assert-count 1 t:SB_RAM40_4K
 
+design -reset; read_verilog ../common/blockram.v
+chparam -set ADDRESS_WIDTH 2 -set DATA_WIDTH 8 sync_ram_sdp
+setattr -set syn_ramstyle "registers" m:memory
+synth_ice40 -top sync_ram_sdp; cd sync_ram_sdp
+select -assert-count 0 t:SB_RAM40_4K # requested FFRAM explicitly
+select -assert-min 1 t:SB_DFFE
+
 design -reset; read_verilog ../common/blockram.v
 chparam -set ADDRESS_WIDTH 2 -set DATA_WIDTH 8 sync_ram_sdp
 setattr -set logic_block 1 m:memory
@@ -67,6 +75,7 @@ synth_ice40 -top sync_ram_sdp; cd sync_ram_sdp
 select -assert-count 0 t:SB_RAM40_4K # requested BROM but this is a RAM
 select -assert-min 1 t:SB_DFFE
 
+# ================================ ROM ================================
 # ROM bits <= 4K; Data width <= 16; Address width <= 11: -> SB_RAM40_4K
 
 design -reset; read_verilog ../common/blockrom.v
@@ -110,6 +119,13 @@ setattr -set rom_block 1 m:memory
 synth_ice40 -top sync_rom; cd sync_rom
 select -assert-count 1 t:SB_RAM40_4K
 
+design -reset; read_verilog ../common/blockrom.v
+chparam -set ADDRESS_WIDTH 2 -set DATA_WIDTH 8 sync_rom
+setattr -set syn_romstyle "logic" m:memory
+synth_ice40 -top sync_rom; cd sync_rom
+select -assert-count 0 t:SB_RAM40_4K # requested LUTROM explicitly
+select -assert-min 1 t:SB_LUT4
+
 design -reset; read_verilog ../common/blockrom.v
 chparam -set ADDRESS_WIDTH 2 -set DATA_WIDTH 8 sync_rom
 setattr -set logic_block 1 m:memory