; Let the input B=offset from byte (like if X=1, then B=1. X=7, then B=7.
; You must have already adjusted HL for X position wrt bytes, so if X=9
; then you must've incremented HL by 1 and take the modulo of X so then X is now 1
;IX=location of the sprite. We're only writing one sprite byte. You should know
;what to do with the rest...

 ld a,(ix+0) ;let this be the sprite byte for now.
 ld c,0
 inc b
 dec b      ;checking to see if input B=0
 jr z,$+8   ;jump over rotating if the sprite is actually aligned.
 rrca
 scf
 rr c
 djnz $-4
 ld b,a     ;saving the sprite byte in B
 ld a,(hl)  ;getting the byte from the screen
 xor b      ;masking in the sprite data
 and c      ;removing screen data bits.
 xor b      ;masking sprite data. That which was zero above will have sprite.
 ld (hl),a
 inc hl
 ld a,c
 cpl        ;inverting the sprite mask so we can get the other half in
 ld c,a
 ld a,(hl)
 xor b
 and c
 xor b
 ld (hl),a
 ret        ;sprite byte write is complete. Deal with the incremented HL somehow.