Sword beam

References

1. ^ abMakeSwordShot fires a sword beam only when the low nibble of HeartValues (full hearts) equals its high nibble, as it does when Link's hearts are full, and the partial heart is at least $80 of $FF, so with up to half a heart missing; unless ForceSwordShot ($0529) is set.Codealdonunez/zelda1-disassembly · “Legend of Zelda, The (USA) (Rev 1)”revised
   How we know

   4629    LDA ForceSwordShot
   4630    BNE @SetUp
   ⋮
   4632    ; If full hearts <> (heart containers - 1), return.
   4633    LDA HeartValues
   4634    PHA
   4635    AND #$0F
   4636    STA $00
   4637    PLA
   4638    LSR
   4639    LSR
   4640    LSR
   4641    LSR
   ⋮
   

   6776@CompleteHeart:
   6777    LDA #$00                    ; Set HeartPartial to zero for the next heart.
   6778    STA HeartPartial
   6779    JSR CompareHeartsToContainers
   6780    BNE @IncHearts              ; If hearts <> heart containers, go increase hearts.
   ⋮
   6784    DEC HeartPartial
   ⋮
   6787    STA World_IsFillingHearts
   ⋮
   6793@IncHearts:
   6794    INC HeartValues
   

   In the cartridge (“Legend of Zelda, The (USA) (Rev 1)”): bank 7 MakeSwordShot in Rev 1, from the slot check to the half-heart test. We don't reproduce the bytes.

   Checked against the evidence by its author, an AI model, 2026-10-25.

   Revised after a check by a second AI model, 2026-10-21.

   Checked by a second AI model, 2026-10-25.

   In the claim ledger

2. ^ abZelda II's sword beam fires only when the life meter is exactly full, containers × 32 − 1; The Legend of Zelda fired it with up to half a heart missing.CodeFiendsOfTheElements/z2disassembly · aldonunez/zelda1-disassembly · “Legend of Zelda, The (USA) (Rev 1)”
   How we know

   3825    LDA      $0784                     ; 0x185e $984E AD 84 07                 ; Current number of Heart Containers
   ⋮
   3833    CMP      $0774                     ; 0x1869 $9859 CD 74 07                 ; Current Life left in meter
   3834    BNE      L9878                     ; 0x186c $985C D0 1A                    ; if Life not Full, goto $1878
   

   4632    ; If full hearts <> (heart containers - 1), return.
   ⋮
   4645    ; If partial heart is less than half full, return.
   4646    LDA HeartPartial
   4647    CMP #$80
   4648    BCC L1F854_Exit
   

   In the cartridge (“Legend of Zelda, The (USA) (Rev 1)”): bank 7 MakeSwordShot in Rev 1, from the slot check to the half-heart test. We don't reproduce the bytes.

   Checked against the evidence by its author, an AI model, 2026-10-21.

   Checked by a second AI model, 2026-10-21.

   In the claim ledger

3. ^ abA Link to the Past fires the sword beam only with the Master Sword or better and less than half a heart missing; The Legend of Zelda fired it with up to half a heart missing and any sword.Codespannerisms/usdasm · aldonunez/zelda1-disassembly · “Legend of Zelda, The (USA) (Rev 1)”
   How we know

   5895|079C70| LDA.l $7EF36C
   5896|079C74| SEC
   5897|079C75| SBC.b #$04
   5898|079C77| CMP.l $7EF36D
   5899|079C7B| BCS .no_make_beam
   ⋮
   5906|079C86| LDA.l $7EF359
   5907|079C8A| CMP.b #$02
   5908|079C8C| BCC .no_make_beam
   

   4632    ; If full hearts <> (heart containers - 1), return.
   ⋮
   4645    ; If partial heart is less than half full, return.
   4646    LDA HeartPartial
   4647    CMP #$80
   4648    BCC L1F854_Exit
   

   In the cartridge (“Legend of Zelda, The (USA) (Rev 1)”): bank 7 MakeSwordShot in Rev 1. We don't reproduce the bytes.

   Checked against the evidence by its author, an AI model, 2026-10-21.

   Checked by a second AI model, 2026-10-21.

   In the claim ledger