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ReC98/th05/formats/super_roll_put_16x16_m.asm

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[Reverse-engineering] [th05] Micro-optimized monochrome 16×16 sprite display Might as well cover this one while I've got this type of function in my head. This one is used for the animated star backgrounds during Stage 2 and the Shinki battle. Completes P0073, funded by [Anonymous] and -Tom-.
2020-02-08 15:30:23 +00:00
public Z_SUPER_ROLL_PUT_16X16_MONO_RAW
z_super_roll_put_16x16_mono_raw proc near
; Parameters
[Maintenance] Reimplement TASM's ARG directive for `MOV BX, SP` functions `cPtrSize` is simply the wrong constant for calculating parameter offsets on the stack, because it corresponds to the memory model's default distance, not the function's distance. Luckily, ARG has a RETURNS clause, and if you declare all parameters in there, ARG won't emit that pesky and unnecessary `ENTER 0, 0` instruction. Big discovery right there! Sadly, ARG is unusable for ZUN's silly functions that keep the base pointer in BX. TASM declares the resulting equates as `[BP+offset]`, and it's apparently impossible to only get `offset` out of such an equate later. So, rather than staying with numbers, let's reimplement ARG for these functions instead. This way, we can even abstract away the stack clear size for the `RET` instructions. It's a bit rough around the edges though, forcing you to explicitly specify the function distance, and to pass the parameters in reverse order compared to the C declaration (thankfully, all of these use the PASCAL calling convention). It also doesn't work with more complex types yet. But certainly better than numbers. Part of P0134, funded by [Anonymous].
2021-02-10 11:51:14 +00:00
arg_bx near, @patnum:word
[Reverse-engineering] [th05] Micro-optimized monochrome 16×16 sprite display Might as well cover this one while I've got this type of function in my head. This one is used for the animated star backgrounds during Stage 2 and the Shinki battle. Completes P0073, funded by [Anonymous] and -Tom-.
2020-02-08 15:30:23 +00:00
@@left equ cx
@@top equ ax
; Locals
@@PATTERN_HEIGHT = 16
@@rows_left equ ch
@@carry_pixels equ bl
push ds
push si
push di
mov di, @@top
shl @@top, 2
add di, @@top
shl di, 4
mov ax, @@left
shr ax, 3
add di, ax
[Maintenance] Reimplement TASM's ARG directive for `MOV BX, SP` functions `cPtrSize` is simply the wrong constant for calculating parameter offsets on the stack, because it corresponds to the memory model's default distance, not the function's distance. Luckily, ARG has a RETURNS clause, and if you declare all parameters in there, ARG won't emit that pesky and unnecessary `ENTER 0, 0` instruction. Big discovery right there! Sadly, ARG is unusable for ZUN's silly functions that keep the base pointer in BX. TASM declares the resulting equates as `[BP+offset]`, and it's apparently impossible to only get `offset` out of such an equate later. So, rather than staying with numbers, let's reimplement ARG for these functions instead. This way, we can even abstract away the stack clear size for the `RET` instructions. It's a bit rough around the edges though, forcing you to explicitly specify the function distance, and to pass the parameters in reverse order compared to the C declaration (thankfully, all of these use the PASCAL calling convention). It also doesn't work with more complex types yet. But certainly better than numbers. Part of P0134, funded by [Anonymous].
2021-02-10 11:51:14 +00:00
mov bx, @patnum
[Reverse-engineering] [th05] Micro-optimized monochrome 16×16 sprite display Might as well cover this one while I've got this type of function in my head. This one is used for the animated star backgrounds during Stage 2 and the Shinki battle. Completes P0073, funded by [Anonymous] and -Tom-.
2020-02-08 15:30:23 +00:00
shl bx, 1
mov ds, super_patdata[bx]
xor si, si
mov @@rows_left, @@PATTERN_HEIGHT
and cl, 7
jz short @@BYTEALIGNED
mov dx, 0FFFFh
shr dl, cl
xor dh, dl
test al, 1
jnz short @@ODD
@@EVEN:
cmp di, (RES_Y - @@PATTERN_HEIGHT + 1) * ROW_SIZE
jb short @@EVEN_YLOOP2
even
@@EVEN_YLOOP1:
lodsw
ror ax, cl
mov @@carry_pixels, al
and al, dl
or ax, ax
jz short @@EVEN_YLOOP1_SKIP_BLANK_WORD
mov es:[di], ax
@@EVEN_YLOOP1_SKIP_BLANK_WORD:
and @@carry_pixels, dh
jz short @@EVEN_YLOOP1_SKIP_BLANK_3RD
mov es:[di+2], @@carry_pixels
@@EVEN_YLOOP1_SKIP_BLANK_3RD:
add di, ROW_SIZE
dec @@rows_left
cmp di, PLANE_SIZE
jb short @@EVEN_YLOOP1
sub di, PLANE_SIZE
nop
@@EVEN_YLOOP2:
lodsw
ror ax, cl
mov @@carry_pixels, al
and al, dl
or ax, ax
jz short @@EVEN_YLOOP2_SKIP_BLANK_WORD
mov es:[di], ax
@@EVEN_YLOOP2_SKIP_BLANK_WORD:
and @@carry_pixels, dh
jz short @@EVEN_YLOOP2_SKIP_BLANK_3RD
mov es:[di+2], @@carry_pixels
@@EVEN_YLOOP2_SKIP_BLANK_3RD:
add di, ROW_SIZE
dec @@rows_left
jnz short @@EVEN_YLOOP2
jmp short @@RETURN
; ---------------------------------------------------------------------------
@@BYTEALIGNED:
cmp di, (RES_Y - @@PATTERN_HEIGHT + 1) * ROW_SIZE
jb short @@BYTEALIGNED_YLOOP2
even
@@BYTEALIGNED_YLOOP1:
lodsw
or ax, ax
jz short @@BYTEALIGNED_YLOOP1_SKIP_BLANK
mov es:[di], ax
@@BYTEALIGNED_YLOOP1_SKIP_BLANK:
add di, ROW_SIZE
dec @@rows_left
cmp di, (ROW_SIZE * RES_Y)
jb short @@BYTEALIGNED_YLOOP1
sub di, (ROW_SIZE * RES_Y)
even
@@BYTEALIGNED_YLOOP2:
lodsw
or ax, ax
jz short @@BYTEALIGNED_YLOOP2_SKIP_BLANK
mov es:[di], ax
@@BYTEALIGNED_YLOOP2_SKIP_BLANK:
add di, ROW_SIZE
dec @@rows_left
jnz short @@BYTEALIGNED_YLOOP2
jmp short @@RETURN
; ---------------------------------------------------------------------------
@@ODD:
cmp di, (RES_Y - @@PATTERN_HEIGHT + 1) * ROW_SIZE
jb short @@ODD_YLOOP2
even
@@ODD_YLOOP1:
lodsw
ror ax, cl
mov bh, al
and al, dl
jz short @@ODD_YLOOP1_SKIP_BLANK_1ST
mov es:[di], al
@@ODD_YLOOP1_SKIP_BLANK_1ST:
and bh, dh
mov @@carry_pixels, ah
or bx, bx
jz short @@ODD_YLOOP1_SKIP_BLANK_WORD
mov es:[di+1], bx
@@ODD_YLOOP1_SKIP_BLANK_WORD:
add di, ROW_SIZE
dec @@rows_left
cmp di, PLANE_SIZE
jb short @@ODD_YLOOP1
sub di, PLANE_SIZE
even
@@ODD_YLOOP2:
lodsw
ror ax, cl
mov bh, al
and al, dl
jz short @@ODD_YLOOP2_SKIP_BLANK_1ST
mov es:[di], al
@@ODD_YLOOP2_SKIP_BLANK_1ST:
and bh, dh
mov @@carry_pixels, ah
or bx, bx
jz short @@ODD_YLOOP2_SKIP_BLANK_WORD
mov es:[di+1], bx
@@ODD_YLOOP2_SKIP_BLANK_WORD:
add di, ROW_SIZE
dec @@rows_left
jnz short @@ODD_YLOOP2
@@RETURN:
pop di
pop si
pop ds
[Maintenance] Reimplement TASM's ARG directive for `MOV BX, SP` functions `cPtrSize` is simply the wrong constant for calculating parameter offsets on the stack, because it corresponds to the memory model's default distance, not the function's distance. Luckily, ARG has a RETURNS clause, and if you declare all parameters in there, ARG won't emit that pesky and unnecessary `ENTER 0, 0` instruction. Big discovery right there! Sadly, ARG is unusable for ZUN's silly functions that keep the base pointer in BX. TASM declares the resulting equates as `[BP+offset]`, and it's apparently impossible to only get `offset` out of such an equate later. So, rather than staying with numbers, let's reimplement ARG for these functions instead. This way, we can even abstract away the stack clear size for the `RET` instructions. It's a bit rough around the edges though, forcing you to explicitly specify the function distance, and to pass the parameters in reverse order compared to the C declaration (thankfully, all of these use the PASCAL calling convention). It also doesn't work with more complex types yet. But certainly better than numbers. Part of P0134, funded by [Anonymous].
2021-02-10 11:51:14 +00:00
ret_bx
z_super_roll_put_16x16_mono_raw endp
[Reverse-engineering] [th05] Micro-optimized monochrome 16×16 sprite display Might as well cover this one while I've got this type of function in my head. This one is used for the animated star backgrounds during Stage 2 and the Shinki battle. Completes P0073, funded by [Anonymous] and -Tom-.
2020-02-08 15:30:23 +00:00
even