ASM indentation style
Moderator: Moderators
Re: ASM indentation style
I don't indent code, and it barely ever caused any problems. Basically I use vertical spacing when apropriate to make up for the lack of indentation. Also I use local labels such as _loop in order to make things clearer, and sometimes _loop2 for an outer loop, etc.... I use _next when it's the equivalent to a "break" instruction in a higher level language.
One of the point of coding in assembly is not being bound by structures of higher level langusages. For example you can have two loops crossing eachother, a subroutine calling it's own end, or particular cases or stufflike that. This defeats the purpose of indenting completely.
EDIT : Sometimes I label loops according to what they do, such as _wordloop for a loop decoding words in a text, the inner loop decoding letters and the outer loop decoding the entiere line
One of the point of coding in assembly is not being bound by structures of higher level langusages. For example you can have two loops crossing eachother, a subroutine calling it's own end, or particular cases or stufflike that. This defeats the purpose of indenting completely.
EDIT : Sometimes I label loops according to what they do, such as _wordloop for a loop decoding words in a text, the inner loop decoding letters and the outer loop decoding the entiere line
Re: ASM indentation style
@pwnskar
For the lack of use of indentation, I guess it must be because I started to write assembler this way and saw code formatted this way ~25 years ago. It is possible that maybe the assembler was forcing it but I cannot tell since I was barely copying how other people were doing it in those days and my knowledge of programming was still in its infancy ^^;;;
For the lack of use of indentation, I guess it must be because I started to write assembler this way and saw code formatted this way ~25 years ago. It is possible that maybe the assembler was forcing it but I cannot tell since I was barely copying how other people were doing it in those days and my knowledge of programming was still in its infancy ^^;;;
-
- Posts: 1565
- Joined: Tue Feb 07, 2017 2:03 am
Re: ASM indentation style
oh to be clear
ldx #8
L1
lda thing,x
sta place,x
dex
bne L1
..
Is the standard and only way it was done back in the day. Its all well and good to have modern sensibilities but when you are coding on a C64 with no TAB key, 40 columns and every character uses precious precious RAM and CPU cycles. Or a 5K 22column VIC20 or a 4K PET or APPLE ][. You keep label as short as possible <6 is the "standard"(if you are using a C64, on a 4/5K machine there is no room for labels.) Using Line editors while giving you more cpu power, makes typing painful. And when you have a 4~30mins Assemble you do everything you can to make it faster. Whitespace slows you down.
So even when we got to 80 column screens we used it as 2 40 col screens as there was no mouse, F12, PgUp PGDown, Bookmarks, autocomplete, other handy documents etc so being able to keep 1 half of the screen on variable names was very handy.
See also C
K&R style iswhich is nice as it cuts down the number of lines and the number of lines you need to edit and the number of lines the code need to parse etc.
These days Stroustrup style is more popular
ldx #8
L1
lda thing,x
sta place,x
dex
bne L1
..
Is the standard and only way it was done back in the day. Its all well and good to have modern sensibilities but when you are coding on a C64 with no TAB key, 40 columns and every character uses precious precious RAM and CPU cycles. Or a 5K 22column VIC20 or a 4K PET or APPLE ][. You keep label as short as possible <6 is the "standard"(if you are using a C64, on a 4/5K machine there is no room for labels.) Using Line editors while giving you more cpu power, makes typing painful. And when you have a 4~30mins Assemble you do everything you can to make it faster. Whitespace slows you down.
So even when we got to 80 column screens we used it as 2 40 col screens as there was no mouse, F12, PgUp PGDown, Bookmarks, autocomplete, other handy documents etc so being able to keep 1 half of the screen on variable names was very handy.
See also C
K&R style is
Code: Select all
void myFunction(bool var) {
some code here
}
These days Stroustrup style is more popular
Code: Select all
void myFunction(bool var)
{
some code here
}
Re: ASM indentation style
That's excellent! Probably the best that could be done without program-structure macros. With them, I might modify it to the following. Note that no labels are needed except the two I left at and near the top as entry points. Hopefully I didn't make any mistakes, as I was quickly converting the form without focusing much on the bigger picture of what the program is doing. The section of triple-nested IF's could stand some more comments.pwnskar wrote:I sort of follow what I'm used to from other languages just because it makes things easier for me to read and wrap my head around. I'm not super consistent with it but for me that's not really the point. I just want to be able to read and understand what I'm doing with the code, so with that I usually do a lot of comments and little "TODO" notes.
I'll follow Banshaku's example and show you my take on the same task.
I'm surprised so many people seem to not do indentation! For me that simply wouldn't work. My mind needs some visual aide even to just help my eye find it's way back to the right spot on the screen when going back and forth between all my source files.Code: Select all
BufferOffsetBackgroundPalette: ; a = how much to subtract from currently loaded palette. ; TODO: if the palette pointers have not been set yet, do something to handle that. ldx palette_bkg_ptr_lo ldy palette_bkg_ptr_hi stx curr_pointer_lo sty curr_pointer_hi ldx #15 jmp BufferOffsetPalette BufferOffsetSpritePalette: ; a = how much to subtract from currently loaded palette. ldx palette_sprites_ptr_lo ldy palette_sprites_ptr_hi stx curr_pointer_lo sty curr_pointer_hi ldx #31 BufferOffsetPalette: ; x = palette_buffer end index pha ; how much to subtract lda nmi_flags and #NMI_UPDATE_PALETTE_CLEAR sta nmi_flags ldy #15 @offsetloop: pla pha ; push this for next loop iteration clc adc (curr_pointer_lo), y ; offset palette value with a pha ; push this so we can use a for some logic ; first, lets knock down all $xE and $xF to $xD and #%00001111 cmp #$0e bcc @no_xE ; we've determined that the value must be $xE or $xF ; knock it down to $xD pla ; retrieve offset palette value and #%11110000 ora #%00001101 jmp @xEset @no_xE: pla ; retrieve offset palette value @xEset: ; TODO: determine if the offset was positive or negative. ; we could do that by temporarily storing a in the buffer and digging out the initial offset by pla sta palette_buffer, x pla ; retrieve original offset value pha ; and push it again for next loop itteration. bpl @offsetispositive @offsetisnegative: lda palette_buffer, x cmp #$20 bne @not20 lda #$10 sta palette_buffer, x ;jmp @offset_adjusted_by_direction @not20: jmp @offset_adjusted_by_direction @offsetispositive: lda palette_buffer, x cmp #$1d bne @not1d lda #$2d sta palette_buffer, x jmp @offset_adjusted_by_direction @not1d: cmp #$2d bne @not2d lda #$00 sta palette_buffer, x ;jmp @offset_adjusted_by_direction @not2d: @offset_adjusted_by_direction: lda palette_buffer, x cmp #$3d+1 ; so now we check if any value goes above 3d (out of range) and cap it to either 30 or 0d bcc @nocap ; is the value above 127? cmp #0 bpl @nocap1 ; if the offset was negative, this is our stop lda #$0d jmp @nocap @nocap1 ; this is where we end up if the offset was positive lda #$30 @nocap sta palette_buffer, x dex dey cpy #$ff bne @offsetloop pla ; clean stack from original a value ; TODO: patch all sprite opacity buffers with that of the background palette buffer lda palette_buffer sta palette_buffer+16 ; seems just patching the first entry of the sprite palette buffer is enough.. lda nmi_flags ora #NMI_UPDATE_PALETTE sta nmi_flags rts
Code: Select all
BufferOffsetSpritePalette: ; a = how much to subtract from currently loaded palette.
LDX palette_sprites_ptr_lo
LDY palette_sprites_ptr_hi
STX curr_pointer_lo
STY curr_pointer_hi
LDX #31
BufferOffsetPalette: ; x = palette_buffer end index
PHA ; how much to subtract
LDA nmi_flags
AND #NMI_UPDATE_PALETTE_CLEAR
STA nmi_flags
FOR_Y 15, UP_TO, $FF ; (offset loop)
PLA
PHA ; Copy TOS into A.
CLC
ADC (curr_pointer_lo), Y ; Offset palette value with A.
PHA ; Push this so we can use A for some logic.
AND #%00001111 ; Knock down all $xE and $xF to $xD.
CMP #$0E
IF_CARRY_SET ; We've determined that the value must be $xE or $xF; so
PLA ; knock it down to $xD. First retrieve offset palette value.
AND #%11110000
ORA #%00001101
ELSE_
PLA ; Retrieve offset palette value.
END_IF
; TODO: determine if the offset was positive or negative. We could do that by
; temporarily storing A in the buffer and digging out the initial offset by PLA
STA palette_buffer, X
PLA ; Copy offset from TOS into A.
PHA
IF_NEG ; If it's negative:
LDA palette_buffer, X
CMP #$20
IF_EQ
LDA #$10
STA palette_buffer, X
END_IF
ELSE_ ; But if it's positive:
LDA palette_buffer, X
CMP #$1d
IF_EQ
LDA #$2d
STA palette_buffer, X
ELSE_
CMP #$2d
IF_EQ
LDA #$00
STA palette_buffer, X
END_IF
END_IF
END_IF
LDA palette_buffer, X ; Continue now for offset adjusted by direction:
CMP #$3d+1 ; Now we check if any value goes >3d (out of range) and cap it to either 30 or 0d.
IF_GE ; Is the value above 127? [Shouldn't that say "above 61"?]
CMP #0
IF_LT
LDA #$0d ; If the offset was negative, this is our stop.
ELSE_
LDA #$30 ; This is where we end up if the offset was positive.
END_IF
END_IF
STA palette_buffer, X
DEX
NEXT_Y ; (back to top of offset loop)
PLA ; clean stack from original a value
; TODO: patch all sprite opacity buffers w/ that of the background palette buffer.
LDA palette_buffer
STA palette_buffer+16 ; Seems just patching the first entry of the sprite palette buffer is enough.
LDA nmi_flags
ORA #NMI_UPDATE_PALETTE
STA nmi_flags
RTS
;-------------
http://WilsonMinesCo.com/ lots of 6502 resources
Re: ASM indentation style
I think my reasoning was that at that place in the code we don't know which direction we've offset in. It could probably be reworked a bit, since I'm checking for direction twice, but I've left it that way for now since it works...Garth wrote:Code: Select all
IF_GE ; Is the value above 127? [Shouldn't that say "above 61"?]
I've yet to use macros, but I probably will once I feel more comfortable with regular assembly. I can definitely see how they would make life a little easier. Thanks for the example!
Re: ASM indentation style
This line was immediately following a comparison to $3D+1 which is 62; so branching on the carry flag splits 61, 60, 59,... from 62, 63, 64...pwnskar wrote:I think my reasoning was that at that place in the code we don't know which direction we've offset in. It could probably be reworked a bit, since I'm checking for direction twice, but I've left it that way for now since it works...Garth wrote:Code: Select all
IF_GE ; Is the value above 127? [Shouldn't that say "above 61"?]
I used macros for three decades before I realized there was a way to use them for nestable program structures. Next I need to figure out a way to use them to automatically create and destroy local variables.I've yet to use macros, but I probably will once I feel more comfortable with regular assembly. I can definitely see how they would make life a little easier. Thanks for the example!
http://WilsonMinesCo.com/ lots of 6502 resources
Re: ASM indentation style
No, its the Java-style.Oziphantom wrote:See also C
K&R style isCode: Select all
void myFunction(bool var) { some code here }
Or better known as K&R styleOziphantom wrote:These days Stroustrup style is more popularCode: Select all
void myFunction(bool var) { some code here }
Re: ASM indentation style
K&R is an awful mix, where braces for functions are on their own lines, but braces in control blocks are on the same linecyc wrote: Or better known as K&R style
https://en.wikipedia.org/wiki/Indentati ... #K&R_style
My games: http://www.bitethechili.com