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iigs-game-engine
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Update some comments

This commit is contained in:
Lucas Scharenbroich 2022-02-02 17:24:27 -06:00
parent 5f492fd557
commit 16a3a385a9
2 changed files with 10 additions and 7 deletions
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6
src/blitter/Horz.s
View File

@ -365,7 +365,7 @@ _ApplyBG0XPos
ldx :draw_count_x2
lda :opcode
ldy :base_address
ldy :base_address ; Y-register is preserved, this can be removed
jsr SetCodeEntryOpcode
; If this is an odd entry, also set the odd_entry low byte and save the operand high byte
@ -374,11 +374,11 @@ _ApplyBG0XPos
beq :not_odd
ldx :draw_count_x2
ldy :base_address
ldy :base_address ; Y-register is preserved, this can be removed
jsr SetOddCodeEntry
ldx :draw_count_x2
ldy :base_address
ldy :base_address ; Y-register is preserved, this can be removed
pei :exit_address
jmp :SaveHighOperand ; Only used once, so "inline" it
:save_high_op_rtn

11
src/blitter/Template.s
View File

@ -584,15 +584,18 @@ full_return jml blt_return ; Full exit
; The even/odd branch of this line's exception handler will return here. This is mostly
; a space-saving measure to allow for more code in the exeption handers themselved, but
; also simplified the relocation process since we only have to update a single address
; a space-saving measure to allow for more code in the exeption handers themselves, but
; also simplifies the relocation process since we only have to update a single address
; in each exception handler, rather than two.
;
; Oce working, this code should be able to be interleaved with the r_jmp_rtn code
; Once working, this code should be able to be interleaved with the r_jmp_rtn code
; above to eliminate a couple of branches
jmp_rtn
bvs r_jmp_rtn
jmp_rtn_1 jmp l_jmp_rtn-base ; Could inline the code and save 3 cycles / line
; If we switch even/odd exit points, could fall through
; to the even_exit JMP at the head of the PEA field to
; save 6 cycles.
; Re-enable interrupts and continue -- the even_exit JMP from the previous line will jump here every
; 8 or 16 lines in order to give the system time to handle interrupts.
@ -653,7 +656,7 @@ long_4 stal *+4-base
l_jmp_rtn xba
sep #$20
pha
rep #$61 ; Clear everything C, V and M
rep #$61 ; Clear everything C, V and M
bra even_exit
l_is_jmp sec ; Set the C flag (V is always cleared at this point) which tells a snippet to push only the high byte