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#!/usr/bin/env tclsh
source tclasm_old.tcl
## also look at stack_machine_cond_jump test
## we're going to write numbers from 0 to 639 at addresses h100000 to h1009FC
## and then write non-zero value at h100A00
# this will translate to 3 16-bit instructions
set_sp h0FFFFC
## set up the counter
# each of those 2 will translate to 1 16-bit instruction
const 0
stack down
## this is the point we later jump to, address 10
tee
## compute address: counter * 4 + h100000
stack down
const 4
mul
const h100000
add
stack up
## load computed address to im
exchange_im
## save value of counter at address pointed by im
swap
store
swap
## increase counter by 1
const 1
add
## compare value of counter to 640
tee
stack down
const 640
sub
stack up
## loop if counter != 640
cond_jump 10
## write hFFFFFFFF to address h100A00 (the point is to write a non-zero value
## there, but because our stack machine only knows how to write 32-bit values
## to memory, we'll write to h100A00 and h100A02, both being mapped as the
## VGA power-on register - what matters is the later write, so at least one of
## higher 16 bits of written value has to be non-zero)
const -1
store@ h100A00
halt
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