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Diffstat (limited to 'engine/time.asm')
| -rw-r--r-- | engine/time.asm | 311 |
1 files changed, 311 insertions, 0 deletions
diff --git a/engine/time.asm b/engine/time.asm new file mode 100644 index 000000000..fff52b173 --- /dev/null +++ b/engine/time.asm @@ -0,0 +1,311 @@ +; Functions relating to the timer interrupt and the real-time-clock. + + +AskTimer: ; 591 + push af + ld a, [$ffe9] + and a + jr z, .asm_59a + call Timer + +.asm_59a + pop af + reti +; 59c + + +LatchClock: ; 59c +; latch clock counter data + ld a, 0 + ld [MBC3LatchClock], a + ld a, 1 + ld [MBC3LatchClock], a + ret +; 5a7 + + +UpdateTime: ; 5a7 + call GetClock + call FixDays + call FixTime + callba GetTimeOfDay + ret +; 5b7 + + +GetClock: ; 5b7 +; store clock data in hRTCDayHi-hRTCSeconds + +; enable clock r/w + ld a, SRAM_ENABLE + ld [MBC3SRamEnable], a + +; clock data is 'backwards' in hram + + call LatchClock + ld hl, MBC3SRamBank + ld de, MBC3RTC + + ld [hl], RTC_S + ld a, [de] + and $3f + ld [hRTCSeconds], a + + ld [hl], RTC_M + ld a, [de] + and $3f + ld [hRTCMinutes], a + + ld [hl], RTC_H + ld a, [de] + and $1f + ld [hRTCHours], a + + ld [hl], RTC_DL + ld a, [de] + ld [hRTCDayLo], a + + ld [hl], RTC_DH + ld a, [de] + ld [hRTCDayHi], a + +; unlatch clock / disable clock r/w + call CloseSRAM + ret +; 5e8 + + +FixDays: ; 5e8 +; fix day count +; mod by 140 + +; check if day count > 255 (bit 8 set) + ld a, [hRTCDayHi] ; DH + bit 0, a + jr z, .daylo +; reset dh (bit 8) + res 0, a + ld [hRTCDayHi], a ; DH + +; mod 140 +; mod twice since bit 8 (DH) was set + ld a, [hRTCDayLo] ; DL +.modh + sub 140 + jr nc, .modh +.modl + sub 140 + jr nc, .modl + add 140 + +; update dl + ld [hRTCDayLo], a ; DL + +; unknown output + ld a, $40 ; %1000000 + jr .set + +.daylo +; quit if fewer than 140 days have passed + ld a, [hRTCDayLo] ; DL + cp 140 + jr c, .quit + +; mod 140 +.mod + sub 140 + jr nc, .mod + add 140 + +; update dl + ld [hRTCDayLo], a ; DL + +; unknown output + ld a, $20 ; %100000 + +.set +; update clock with modded day value + push af + call SetClock + pop af + scf + ret + +.quit + xor a + ret +; 61d + + +FixTime: ; 61d +; add ingame time (set at newgame) to current time +; day hr min sec +; store time in CurDay, hHours, hMinutes, hSeconds + +; second + ld a, [hRTCSeconds] ; S + ld c, a + ld a, [StartSecond] + add c + sub 60 + jr nc, .updatesec + add 60 +.updatesec + ld [hSeconds], a + +; minute + ccf ; carry is set, so turn it off + ld a, [hRTCMinutes] ; M + ld c, a + ld a, [StartMinute] + adc c + sub 60 + jr nc, .updatemin + add 60 +.updatemin + ld [hMinutes], a + +; hour + ccf ; carry is set, so turn it off + ld a, [hRTCHours] ; H + ld c, a + ld a, [StartHour] + adc c + sub 24 + jr nc, .updatehr + add 24 +.updatehr + ld [hHours], a + +; day + ccf ; carry is set, so turn it off + ld a, [hRTCDayLo] ; DL + ld c, a + ld a, [StartDay] + adc c + ld [CurDay], a + ret +; 658 + +Function658: ; 658 + xor a + ld [StringBuffer2], a + ld a, $0 + ld [$d089], a + jr .asm_677 + + call UpdateTime + ld a, [hHours] + ld [$d087], a + ld a, [hMinutes] + ld [$d088], a + ld a, [hSeconds] + ld [$d089], a + jr .asm_677 + +.asm_677 + ld a, $5 + ld hl, $40ed + rst FarCall + ret +; 67e + + + +Function67e: ; 67e + call Function685 + call SetClock + ret +; 685 + +Function685: ; 685 + xor a + ld [hRTCSeconds], a + ld [hRTCMinutes], a + ld [hRTCHours], a + ld [hRTCDayLo], a + ld [hRTCDayHi], a + ret +; 691 + + +SetClock: ; 691 +; set clock data from hram + +; enable clock r/w + ld a, SRAM_ENABLE + ld [MBC3SRamEnable], a + +; set clock data +; stored 'backwards' in hram + + call LatchClock + ld hl, MBC3SRamBank + ld de, MBC3RTC + +; seems to be a halt check that got partially commented out +; this block is totally pointless + ld [hl], RTC_DH + ld a, [de] + bit 6, a ; halt + ld [de], a + +; seconds + ld [hl], RTC_S + ld a, [hRTCSeconds] + ld [de], a +; minutes + ld [hl], RTC_M + ld a, [hRTCMinutes] + ld [de], a +; hours + ld [hl], RTC_H + ld a, [hRTCHours] + ld [de], a +; day lo + ld [hl], RTC_DL + ld a, [hRTCDayLo] + ld [de], a +; day hi + ld [hl], RTC_DH + ld a, [hRTCDayHi] + res 6, a ; make sure timer is active + ld [de], a + +; cleanup + call CloseSRAM ; unlatch clock, disable clock r/w + ret +; 6c4 + + +Function6c4: ; 6c4 + xor a + push af + ld a, $0 + call GetSRAMBank + pop af + ld [$ac60], a + call CloseSRAM + ret +; 6d3 + +Function6d3: ; 6d3 + ld hl, $ac60 + push af + ld a, $0 + call GetSRAMBank + pop af + or [hl] + ld [hl], a + call CloseSRAM + ret +; 6e3 + +Function6e3: ; 6e3 + ld a, $0 + call GetSRAMBank + ld a, [$ac60] + call CloseSRAM + ret +; 6ef + |