Efficiency Optimizations

[britlion]

I know, I know - I'm always harping on about this.

1> Does setting array and string indexes to start at 1 - to make it like basic - make for less efficient code?
(that is using the new default for --sinclair that Boriel is presumably putting into the next version)

2> Boriel once mentioned that the default behavior for code like:

Code:

LET A=A+1 LET A=A*2

Was

Code:

ld a, 10 ;Init ld (_A), a ;Load inc a ;Inc ld (_A), a ; Store <<<<< Not needed sla a ; Multiply ld (_A), a ; Store

And that -O3 should remove that extra code. I actually can't tell the difference in the above with or without -O3.

What does -O3 do? My code seems to be remarkably similar. In fact, the runtime routines for almost everything are included still - most of the print system (AT, COLOR, BOLD, ITALIC) even if never used).

Is -O3 doing what it's supposed to? I find most short code seems to be just about the same size, suggesting it isn't cutting down on runtime routines at all.

Actual program used:

Code:

DIM A as byte LET A=5 LET A=A+1 LET A=A*2 PRINT A

Actual -O3 Result:

Code:

E:\ZX\ZXBwork>zxb Test2.bas -A -O3 INFO: __PRINTI8 is not defined. No optimization is done. INFO: PRINT_EOL is not defined. No optimization is done. E:\ZX\ZXBwork>notepad Test2.asm

The produced code was 1134 bytes without -O3 and 1132 bytes with -O3.

The difference is the end of the program. Optimized it does

Code:

ld bc, 0

Unoptimized it closes out with

Code:

ld hl, 0 ld b, h ld c, l

That's the only difference.
These error messages seem a little odd. Am I misusing the -O3 option, somehow? I was expecting it to cut out all the runtimes that wouldn't be needed.

Admittedly in a larger project, most of the runtimes would likely end up being used. I was a little spoiled by the tiny code that the hisoft compiler made, I think :-)

[boriel]

I think, this is best moved to "Whishlist" (TO DO list, wishes, suggestions, etc...) so it won't get buried among other threads.