Merge branch '91-use-external-sd-card-controller' into 'AXI-Rewrite'

.gitmodules

Makefile

hw/super6502_fpga/sources.list

hw/super6502_fpga/src/rtl/super_6502_fpga.sv

hw/super6502_fpga/src/sim/Makefile

hw/super6502_fpga/src/sim/hvl/sim_top.sv

hw/super6502_fpga/src/sim/sources.list

hw/super6502_fpga/src/sim/sub/verilog-sd-emulator

hw/super6502_fpga/src/sub/axi_crossbar

hw/super6502_fpga/src/sub/cpu_wrapper/cpu_wrapper.sv

hw/super6502_fpga/src/sub/rtl-common

hw/super6502_fpga/src/sub/sd_controller

...ga/src/sub/sd_controller_wrapper/sd_controller_wrapper.sv

hw/super6502_fpga/src/sub/sd_controller_wrapper/sdspi

...per6502_fpga/src/sub/sd_controller_wrapper/shadow_regs.sv

hw/super6502_fpga/src/sub/wb2axip

hw/super6502_fpga/super6502_fpga.peri.xml

hw/super6502_fpga/super6502_fpga.xml

init_env.sh

sw/test_code/sd_controller_test/link.ld