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◆ main openmsx / share / scripts / _vdp_access_test.tcl
3.3 KiB · Tcl · last changed chore(): initial commit 1 month ago source blame history raw
e8555c89 Andy McCall 1 
namespace eval vdp_access_test {
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# you can tweak these to test for other stuff
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# TODO: make this flexible so the timing can be specified for each combination
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# of ports and read/write
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variable ioports {0x98 0x99}
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variable cycle_max 29
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# if you set this to true, you can also see OK I/O, but there are many of those!
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variable debug false
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# if you set this to true, openMSX will break when too fast access happens, so
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# you can investigate what's going on with the debug commands (or debugger)
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variable enable_break false
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variable last_access_time 0
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variable last_access_type
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variable last_access_port
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variable is_enabled false
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variable watchpoint_write_id
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variable watchpoint_read_id
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variable address_list
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set_help_text toggle_vdp_access_test \
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"Report in the console when VDP I/O is done which could possibly cause data
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corruption on the slowest VDP (TMS99xx), i.e. when time between successive I/O
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was less than $cycle_max cycles and display was active. Note: this script is
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not 100% accurate! Keep testing on a real MSX as well. The script has some
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tuning options; edit the script to do so, it's explained at the top what can be
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tuned."
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proc check_time {access_type} {
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	variable last_access_time
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	variable last_access_type
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	variable last_access_port
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	variable cycle_max
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	variable debug
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	variable enable_break
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	variable address_list
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	set port [expr {$::wp_last_address & 255}]
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	set current_time [machine_info time]
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	set cycles [expr {round(3579545 * ($current_time - $last_access_time))}]
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	set screen_enabled [expr {[debug read "VDP regs" 1] & 64}]
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	set vblank [expr {[debug read "VDP status regs" 2] & 64}]
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	set pc [format "%04x" [reg PC]]
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	if {($cycles < $cycle_max) && $screen_enabled && !$vblank} {
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		if {$pc ni $address_list} {
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			set valuetext ""
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			if {$access_type eq "write"} {
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				set valuetext [format " (value 0x%02X)" $::wp_last_value]
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			}
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			puts [format "VDP $last_access_type on port 0x%02X followed by a $access_type${valuetext} on port 0x%02X on address $pc and time $current_time with too few cycles in between: $cycles (< $cycle_max)" $last_access_port $port]
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			lappend address_list $pc
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			set address_list [lsort $address_list]
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			puts "Sorted list of addresses where too fast I/O is done: $address_list"
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			if {$enable_break} {
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				debug break
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			}
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		}
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	} else {
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		if {$debug} {
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			if {!$screen_enabled} {
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				set reason "screen is disabled"
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			} elseif {$vblank} {
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				set reason "in vblank"
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			} else {
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				set reason "last access was $cycles cycles ago, >= $cycle_max"
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			}
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			puts [format "VDP I/O $access_type to port 0x%02X OK on address: 0x$pc, $reason" $port]
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		}
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	}
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	set last_access_time $current_time
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	set last_access_port $port
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	set last_access_type $access_type
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}
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proc toggle_vdp_access_test {} {
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	variable is_enabled
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	variable watchpoint_write_id
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	variable watchpoint_read_id
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	variable address_list
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	variable ioports
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	if {!$is_enabled} {
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		set watchpoint_write_id [debug set_watchpoint write_io $ioports {} {vdp_access_test::check_time "write"}]
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		set watchpoint_read_id  [debug set_watchpoint read_io  $ioports {} {vdp_access_test::check_time "read"}]
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		set is_enabled true
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		set address_list [list]
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	} else {
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		debug remove_watchpoint $watchpoint_write_id
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		debug remove_watchpoint $watchpoint_read_id
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		set is_enabled false
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	}
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}
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namespace export toggle_vdp_access_test
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} ;# namespace vdp_access_test
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namespace import vdp_access_test::*