yosys/techlibs/xilinx/lutrams.txt

bram $__XILINX_RAM16X1D
  init 1
  abits 4
  dbits 1
  groups 2
  ports  1 1
  wrmode 0 1
  enable 0 1
  transp 0 0
  clocks 0 1
  clkpol 0 2
endbram

bram $__XILINX_RAM32X1D
  init 1
  abits 5
  dbits 1
  groups 2
  ports  1 1
  wrmode 0 1
  enable 0 1
  transp 0 0
  clocks 0 1
  clkpol 0 2
endbram

bram $__XILINX_RAM64X1D
  init 1
  abits 6
  dbits 1
  groups 2
  ports  1 1
  wrmode 0 1
  enable 0 1
  transp 0 0
  clocks 0 1
  clkpol 0 2
endbram

bram $__XILINX_RAM128X1D
  init 1
  abits 7
  dbits 1
  groups 2
  ports  1 1
  wrmode 0 1
  enable 0 1
  transp 0 0
  clocks 0 1
  clkpol 0 2
endbram


bram $__XILINX_RAM32X6SDP
  init 1
  abits 5
  dbits 6
  groups 2
  ports  1 1
  wrmode 0 1
  enable 0 1
  transp 0 0
  clocks 0 1
  clkpol 0 2
endbram

bram $__XILINX_RAM64X3SDP
  init 1
  abits 6
  dbits 3
  groups 2
  ports  1 1
  wrmode 0 1
  enable 0 1
  transp 0 0
  clocks 0 1
  clkpol 0 2
endbram

bram $__XILINX_RAM32M
  init 1
  abits 5
  dbits 2
  groups 2
  ports  3 1
  wrmode 0 1
  enable 0 1
  transp 0 0
  clocks 0 1
  clkpol 0 2
endbram

bram $__XILINX_RAM64M
  init 1
  abits 6
  dbits 1
  groups 2
  ports  3 1
  wrmode 0 1
  enable 0 1
  transp 0 0
  clocks 0 1
  clkpol 0 2
endbram


# Disabled for now, pending support for LUT4 arches
#   since on LUT6 arches this occupies same area as
#   a RAM32X1D
#match $__XILINX_RAM16X1D
#  min bits 2
#  min wports 1
#  make_outreg
#  or_next_if_better
#endmatch

match $__XILINX_RAM32X1D
  min bits 3
  min wports 1
  make_outreg
  or_next_if_better
endmatch

match $__XILINX_RAM64X1D
  min bits 5
  min wports 1
  make_outreg
  or_next_if_better
endmatch

match $__XILINX_RAM128X1D
  min bits 9
  min wports 1
  make_outreg
  or_next_if_better
endmatch


match $__XILINX_RAM32X6SDP
  min bits 5
  min wports 1
  make_outreg
  or_next_if_better
endmatch

match $__XILINX_RAM64X3SDP
  min bits 6
  min wports 1
  make_outreg
  or_next_if_better
endmatch

match $__XILINX_RAM32M
  min bits 5
  min rports 3
  min wports 1
  make_outreg
  or_next_if_better
endmatch

match $__XILINX_RAM64M
  min bits 5
  min rports 3
  min wports 1
  make_outreg
endmatch