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added string.hash()

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This commit is contained in:
Irmen de Jong 2023-11-26 22:07:05 +01:00
parent 44d232f52a
commit 1dff59e1d6
5 changed files with 61 additions and 121 deletions
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22
compiler/res/prog8lib/string.p8
View File

@ -361,4 +361,26 @@ fail clc ; yes, no match found, return with c=0
rts
}}
}
asmsub hash(str string @R0) -> ubyte @A {
; experimental 8 bit hashing function.
; hash(-1)=179; hash(i) = ROL hash(i-1) XOR string[i]
; (experimental because the quality of the resulting hash value still has to be determined)
%asm {{
lda #179
sta P8ZP_SCRATCH_REG
ldy #0
clc
- lda (cx16.r0),y
beq +
rol P8ZP_SCRATCH_REG
eor P8ZP_SCRATCH_REG
sta P8ZP_SCRATCH_REG
iny
bne -
+ lda P8ZP_SCRATCH_REG
rts
}}
}
}

16
compiler/res/prog8lib/virtual/string.p8
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@ -157,4 +157,20 @@ string {
return false
return compare(st + str_len - suffix_len, suffix) == 0
}
sub hash(str st) -> ubyte {
; experimental 8 bit hashing function.
; hash(-1)=179; hash(i) = ROL hash(i-1) XOR string[i]
; (experimental because the quality of the resulting hash value still has to be determined)
ubyte hashcode = 179
ubyte ix
repeat {
if st[ix] {
rol(hashcode)
hashcode ^= st[ix]
ix++
} else
return hashcode
}
}
}

4
docs/source/libraries.rst
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@ -276,6 +276,10 @@ Provides string manipulation routines.
Returns 1 (true) if the string matches the pattern, 0 (false) if not.
'?' in the pattern matches any one character. '*' in the pattern matches any substring.
``hash (string) -> ubyte``
Returns a simple 8 bit hash value for the given string.
*Experimental.* The quality of the resulting hash value still has to be determined.
floats
------

9
docs/source/todo.rst
View File

@ -2,6 +2,15 @@
TODO
====
- fix wrong result of:
ubyte b = 4
float c
%asm {{
nop
}}
c += b*b
which works if c is a uword instead...
- [on branch: shortcircuit] investigate McCarthy evaluation again? this may also reduce code size perhaps for things like if a>4 or a<2 ....
...

131
examples/test.p8
View File

@ -1,130 +1,19 @@
%import textio
%import string
%zeropage basicsafe
; $3d5
main {
ubyte counter
uword wcounter
ubyte end
uword wend
sub start() {
end=10
for cx16.r2L in 0 to end-1 {
txt.print_ub(cx16.r2L)
str[] names = [iso:"irmen", iso:"jurrian", iso:"houtzaagmolen 41", iso:"the Quick Brown Fox jumps Over the LAZY dog!"]
; txt.iso()
uword name
for name in names {
txt.print_ub(string.hash(name))
txt.spc()
txt.print(name)
txt.nl()
}
txt.nl()
cx16.r2L=0
labeltje:
txt.print_ub(cx16.r2L)
txt.spc()
cx16.r2L++
if cx16.r2L!=end
goto labeltje
txt.nl()
cx16.r0=0
forloops()
txt.print_uw(cx16.r0)
txt.nl()
cx16.r0=0
untilloops()
txt.print_uw(cx16.r0)
txt.nl()
}
sub forloops() {
end=10
for counter in 0 to end {
cx16.r0++
}
for counter in 0 to end-1 {
cx16.r0++
}
end=0
for counter in 0 to end {
cx16.r0++
}
for counter in 0 to end-1 {
cx16.r0++
}
end=255
for counter in 0 to end {
cx16.r0++
}
for counter in 0 to end-1 {
cx16.r0++
}
wend=1000
for wcounter in 0 to wend {
cx16.r0++
}
for wcounter in 0 to wend-1 {
cx16.r0++
}
}
sub untilloops() {
end=10
counter = 0
repeat {
cx16.r0++
if counter==end
break
counter++
}
counter = 0
do {
cx16.r0++
counter++
} until counter==end
end=0
counter = 0
repeat {
cx16.r0++
if counter==end
break
counter++
}
counter = 0
do {
cx16.r0++
counter++
} until counter==end
counter = 0
end=255
repeat {
cx16.r0++
if counter==end
break
counter++
}
counter = 0
do {
cx16.r0++
counter++
} until counter==end
wcounter = 0
wend=1000
repeat {
cx16.r0++
if wcounter==wend
break
wcounter++
}
wcounter = 0
do {
cx16.r0++
wcounter++
} until wcounter==wend
}
}