2012-04-18, 02:10 AM
This is interesting. There's quite a lot of overhead in PLOT, I think - this is fairly unoptimized, still - and appears to be a little buggy. It also doesn't use the screen tables lookup yet. But it's late and I need to go to bed 
Code:
SUB plotPoint (x as uByte, y as uByte)
ASM
ld d,(IX+5) ;'X
ld e,(IX+7) ;'Y
ld a, 191
sub e
ret c
ld e, a
and a
rra
scf
rra
and a
rra
xor e
and 248
xor e
ld h, a
ld a, d
rlca
rlca
rlca
xor e
and 199
xor e
rlca
rlca
ld l, a
ld a, d
and 7
ld b, a
inc b
ld a, 1
plotPoint_loop:
rrca
djnz plotPoint_loop
;cpl
ld b, a
ld a, (hl)
or b
ld (hl), a
END ASM
END SUB
FUNCTION t() as uLong
asm
DI
LD DE,(23674)
LD D,0
LD HL,(23672)
EI
end asm
end function
dim time0, time1, time2 as long
dim n as uInteger
cls
for n=1 to 150
plotPoint(n,n-1)
plot n,n+3
next n
time0=t()
for n=0 to 50000
plot 50,50
next n
time1=t()
for n=0 to 50000
plotPoint(50,50)
next n
time2=t()
print "ZX Basic 50,000 plot:"
print time1-time0;"frames =";(time1-time0)/cast(float,50);" seconds"
print
print "plotPoint 50,000 times:"
print time2-time1;"frames=";(time2-time1)/cast(float,50);" seconds"