Posted on May 17, 2011 at 10:18Hi,
low level routines such as integer multiply are wrtitten in assembler (by the compiler company) anyway.
For example, here is what you get with Cosmic:
; INTEGER MULTIPLY
; Copyright (c) 1998 by COSMIC Software
; - 1st operand in X:A
; - 2nd operand in Y and extension
;
xdef c_imul
xref.b c_y
.dcall ''3,0,c_imul''
;
c_imul:
push a ; save LSB1
ld a,y ; load LSB2
mul x,a ; H * L
ld c_y+1,a ; save in memory
ld x,c_y ; load MSB2
pop a ; load LSB1
push a ; and save it
mul x,a ; L * H
add a,c_y+1 ; accumulate
ld c_y+1,a ; and store
pop a ; load LSB1
ld x,y ; load LSB2
mul x,a ; L * L
push a ; save LSB
ld a,x ; accumulate
add a,c_y+1 ; MSB
ld x,a ; in place
pop a ; restore LSB result
ret ; and return
;
end
this executes in 122 cycles, which, I guess, is consistent with the timing you measured (just multiply by the internal frequency you are using to check).
Conclusion is, there seem to be no solution to your problem.
Hope this helps.
Regards,
Luca
PS: if you think multiplication is slow, don't even try the division...
