bram $__ICE40_RAM4K_M0
  init 1
  abits 8
  dbits 16
  groups 2
  ports  1  1
  wrmode 0  1
  enable 1 16
  transp 0  0
  clocks 2  3
  clkpol 2  3
endbram

bram $__ICE40_RAM4K_M123
  init 1
  abits  9 @M1
  dbits  8 @M1
  abits 10 @M2
  dbits  4 @M2
  abits 11 @M3
  dbits  2 @M3
  groups 2
  ports  1 1
  wrmode 0 1
  enable 1 1
  transp 0 0
  clocks 2 3
  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 $__ICE40_RAM4K_M0
  # 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 efficiency 2
  make_transp
  or_next_if_better
endmatch

match $__ICE40_RAM4K_M0
  # explicitly requested RAM
  attribute syn_ramstyle=block_ram ram_block
  attribute !syn_romstyle
  attribute !rom_block
  attribute !logic_block
  min wports 1
  make_transp
  or_next_if_better
endmatch

match $__ICE40_RAM4K_M0
  # explicitly requested ROM
  attribute syn_romstyle=ebr rom_block
  attribute !syn_ramstyle
  attribute !ram_block
  attribute !logic_block
  max wports 0
  make_transp
  or_next_if_better
endmatch

match $__ICE40_RAM4K_M123
  # 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 efficiency 2
  make_transp
  or_next_if_better
endmatch

match $__ICE40_RAM4K_M123
  # explicitly requested RAM
  attribute syn_ramstyle=block_ram ram_block
  attribute !syn_romstyle
  attribute !rom_block
  attribute !logic_block
  min wports 1
  make_transp
  or_next_if_better
endmatch

match $__ICE40_RAM4K_M123
  # explicitly requested ROM
  attribute syn_romstyle=ebr rom_block
  attribute !syn_ramstyle
  attribute !ram_block
  attribute !logic_block
  max wports 0
  make_transp
endmatch