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# write RAM code (a sequence of nops followed by ret)
li x5,0x00000013 # nop
sw x5,4(x0)
sw x5,8(x0)
sw x5,12(x0)
sw x5,16(x0)
sw x5,20(x0)
sw x5,24(x0)
sw x5,28(x0)
sw x5,32(x0)
sw x5,36(x0)
sw x5,40(x0)
sw x5,44(x0)
sw x5,48(x0)
sw x5,52(x0)
sw x5,56(x0)
sw x5,60(x0)
sw x5,64(x0)
sw x5,68(x0)
sw x5,72(x0)
sw x5,76(x0)
sw x5,80(x0)
sw x5,84(x0)
sw x5,88(x0)
sw x5,92(x0)
sw x5,96(x0)
sw x5,100(x0)
sw x5,104(x0)
sw x5,108(x0)
sw x5,112(x0)
sw x5,116(x0)
sw x5,120(x0)
sw x5,124(x0)
sw x5,128(x0)
sw x5,132(x0)
sw x5,136(x0)
sw x5,140(x0)
sw x5,144(x0)
sw x5,148(x0)
sw x5,152(x0)
sw x5,156(x0)
sw x5,160(x0)
sw x5,164(x0)
sw x5,168(x0)
sw x5,172(x0)
sw x5,176(x0)
sw x5,180(x0)
sw x5,184(x0)
sw x5,188(x0)
sw x5,192(x0)
li x5,0x00008067 # ret
sw x5,196(x0)
# setup gpio address in x5
li x5,0x02000000
sw x0,0(x5)
# initial entry point into RAM code
li x3,4
# initialize RAM counter
sw x0,0(x0)
# start of loop. remember this address
auipc x4,0
# execute RAM code, come back here
jalr x3
# load counter and increment
lw x6,0(x0)
addi x6,x6,1
# store counter and update gpios
sw x6,0(x5)
sw x6,0(x0)
# calculate new entry point into RAM code
slli x3,x6,2
andi x3,x3,127
addi x3,x3,32
# execute RAM code, come back to start of loop
mv x1,x4
jr x3
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