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[Reverse-engineering] [th05] Rank-based speed adjustment 

Again, one of these functions that ZUN *probably* wrote in ASM for shits
and giggles, which you *again could* "decompile" using in-line assembly,
but that kind of defeats the point.
Oh well, at least the fact that the parameter is passed in AL means that
the calling convention must have been __fastcall, and *that* part *does*
cleanly map to C. Unlike some of the functions in d08a7f4.

Funded by zorg.
This commit is contained in:
nmlgc 2018-12-12 20:38:08 +01:00
parent 807df3d5a7
commit ac7e6bc176
2 changed files with 26 additions and 29 deletions
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20
th05/playperf_adjust_speed.asm Normal file
View File

@ -0,0 +1,20 @@
; unsigned char __fastcall playperf_adjust_speed(unsigned char speed)
public @playperf_adjust_speed
@playperf_adjust_speed proc near
shr al, 1
mov cl, al
mul _playperf
shr ax, 5
add al, cl
cmp al, 128
jbe short @@below_8?
mov al, 128
@@below_8?:
cmp al, 8
jnb short @@ret
mov al, 8
@@ret:
ret
@playperf_adjust_speed endp

35
th05_main.asm
View File

@ -21691,31 +21691,8 @@ arg_4 = word ptr 8
retn 6
sub_15A24 endp
; ---------------------------------------------------------------------------
nop
; =============== S U B R O U T I N E =======================================
sub_15A42 proc near
shr al, 1
mov cl, al
mul _playperf
shr ax, 5
add al, cl
cmp al, 128
jbe short loc_15A55
mov al, 128
loc_15A55:
cmp al, 8
jnb short locret_15A5B
mov al, 8
locret_15A5B:
retn
sub_15A42 endp
include th05/playperf_adjust_speed.asm
; =============== S U B R O U T I N E =======================================
@ -22042,7 +22019,7 @@ loc_15C81:
cmp byte_25346, 0
jnz short loc_15C91
mov al, byte ptr word_26006+1
call sub_15A42
call @playperf_adjust_speed
mov byte ptr word_26006+1, al
loc_15C91:
@ -25157,7 +25134,7 @@ var_2 = word ptr -2
push si
push di
mov al, byte ptr _laser_template.shootout_speed
call sub_15A42
call @playperf_adjust_speed
mov ah, 0
mov [bp+var_2], ax
mov si, offset _lasers
@ -32502,7 +32479,7 @@ var_2 = word ptr -2
push si
push di
mov al, byte_2BC88
call sub_15A42
call @playperf_adjust_speed
mov ah, 0
mov [bp+var_2], ax
mov si, 0B2AAh
@ -34754,7 +34731,7 @@ var_2 = word ptr -2
push si
push di
mov al, byte_2BC88
call sub_15A42
call @playperf_adjust_speed
mov ah, 0
mov [bp+var_2], ax
mov _circles_color, GC_RG
@ -36099,7 +36076,7 @@ var_2 = word ptr -2
push si
push di
mov al, byte_2BC88
call sub_15A42
call @playperf_adjust_speed
mov ah, 0
mov [bp+var_2], ax
mov si, 0B2AAh