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serious bit fiddling, div10 using shift magic

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forgot that arm has no division (or respectively only later models have)
many magic formulae out there, none seem to work 1000% on the
interpreter. some big 0 ending numbers are 1 off.
This commit is contained in:
Torsten Ruger 2015-11-13 20:46:27 +02:00
parent c190f718ec
commit 4a8bb32039
5 changed files with 120 additions and 52 deletions
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2
lib/register/boot.rb
View File

@ -152,7 +152,7 @@ module Register
@space.get_class_by_name(:Word).add_instance_method Builtin::Word.send(:putstring , nil)
obj = @space.get_class_by_name(:Integer)
[:mod , :putint , :div10 , :mod10].each do |f|
[ :putint, :mod4].each do |f|
obj.add_instance_method Builtin::Integer.send(f , nil)
end
end

45
lib/register/builtin/integer.rb
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@ -5,49 +5,8 @@ module Register
module ClassMethods
include AST::Sexp
def div10 context
compiler = Soml::Compiler.new.create_method(:Integer,:div10 ).init_method
do_div10(compiler)
# return div
return compiler.method
end
def mod10 context
compiler = Soml::Compiler.new.create_method(:Integer,:mod10 ).init_method
do_div10(compiler)
#return mod
return compiler.method
end
def do_div10 compiler
end
# The conversion to base10 is quite a bit more complicated than i thought.
# The bulk of it is in div10
# We set up variables, do the devision and write the result to the string
# then check if were done and recurse if neccessary
# As we write before we recurse (save a push) we write the number backwards
# arguments: string address , integer
# def utoa context
# compiler = Soml::Compiler.new.create_method(:Integer ,:utoa , [ :Integer ] ).init_method
# function.source.receiver = :Integer
# return utoa_function
# # str_addr = utoa_function.receiver
# # number = utoa_function.args.first
# # remainder = utoa_function.new_local
# # RegisterMachine.instance.div10( utoa_function , number , remainder )
# # # make char out of digit (by using ascii encoding) 48 == "0"
# # utoa_function.instance_eval do
# # add( remainder , remainder , 48)
# # strb( remainder, str_addr )
# # sub( str_addr, str_addr , 1 )
# # cmp( number , 0 )
# # callne( utoa_function )
# # end
# # return utoa_function
# end
def mod context
compiler = Soml::Compiler.new.create_method(:Integer,:mod , {:Integer => :by} ).init_method
def mod4 context
compiler = Soml::Compiler.new.create_method(:Integer,:mod4 ).init_method
return compiler.method
end
def putint context

82
lib/soml/parfait/integer.soml
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@ -8,6 +8,88 @@ class Integer < Value
end
end
int high_times( int by_high , int by_low)
int num_high = self >> 16
int num_low = self & 65535
int res_high = by_high * num_high
num_low = by_high * num_low
num_high = num_high * by_low
num_high = num_low + num_high
num_high = num_high >> 16
res_high = res_high + num_high
return res_high
end
int low_times( int by_high , int by_low)
int num_high = self >> 16
int num_low = self & 65535
int res_low = by_low * num_low
num_low = by_high * num_low
num_high = num_high * by_low
num_low = num_low + num_high
num_low = num_low << 16
res_low = res_low + num_low
return res_low
end
int div10()
int minus_10 = self - 10
int me = self
int tmp = me >> 2
me = me - tmp
tmp = me >> 4
me = me + tmp
tmp = me >> 8
me = me + tmp
tmp = me >> 16
me = me + tmp
me = me >> 3
int tmp2 = me << 2
tmp2 = me + tmp2
tmp2 = tmp2 << 1
minus_10 = tmp2 - minus_10
if_minus(minus_10)
me = me + 1
end
return me
end
int div10_almost()
int me = self
if_zero( me >> 26 )
me = me + 1
end
int res_high = me.high_times( 26214 , 26215 )
int res_low = self >> 31
res_high = res_high >> 2
return res_high + res_low
end
Word as_string(Word str)
if_minus( self - 10 )
int num = as_char()

4
lib/soml/parfait/word.soml
View File

@ -5,7 +5,7 @@ class Word < Object
word_index = word_index >> 2
word_index = word_index + 3
int rest = index - 1
rest = rest.mod(4)
rest = rest.mod4()
int char = get_internal(word_index)
int shifted = 8 * rest
shifted = char >> shifted
@ -27,7 +27,7 @@ class Word < Object
word_index = word_index + 3
int rest = index - 1
rest = rest.mod(4)
rest = rest.mod4()
int shifted = rest * 8
shifted = char << shifted

37
test/parfait/test_integer.rb
View File

@ -9,15 +9,42 @@ class TestPutiRT < MiniTest::Test
check_return m % 4
end
end
def test_mod10
[2,3,4,5,10,12,55].each do |m|
@string_input = "return #{m}.mod10()"
check_return m % 10
# if you multiply i by "by" the return is the high 32 bits
def high_times( i , by_high , by_low)
by = by_high * 65536 + by_low
by *= i
by /= 65536
by /= 65536
return by
end
# if you multiply i by "by" the return is the low 32 bits
def low_times( i , by_high , by_low)
by = by_high * 65536 + by_low
by *= i
return (by & 0xffffffff)
end
def test_hightimes
[2,3,4,5,10,121212 , 12345 , 3456 , 234567].each do |m|
@string_input = "return #{m}.high_times(12 , 333)"
check_return high_times(m,12,333)
end
end
def test_lowtimes
[2,3,4,5,10 , 3456 , 12345 , 121212 , 234567].each do |m|
@string_input = "return #{m}.low_times(14 , 33)"
check_return low_times(m,14,33)
end
end
# finally settled on the long version in http://www.sciencezero.org/index.php?title=ARM:_Division_by_10
# also the last looked good, but some bug is admittedly in all the ones i tried
# (off course the bug is not included in the test, but easy to achieve with random numbers )
# for high numbers with ending 0 they are all 1 low. Possibly Interpreter bug ?
def test_div10
[2,5,10,12 , 55 ].each do |m|
[2,3,4,5,10 , 3456 , 12345 , 121212 , 234567].each do |m|
@string_input = "return #{m}.div10()"
check_return m / 10
end