Tactics: FRMIS

       Name: FRMIS                                                   [Show more]
       Type: Subroutine
   Category: Tactics
    Summary: Fire a missile from our ship
    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * Main flight loop (Part 3 of 16) calls FRMIS


 We fired a missile, so send it streaking away from us to unleash mayhem and
 destruction on our sworn enemies.


.FRMIS

 LDX #MSL               \ Call FRS1 to launch a missile straight ahead of us
 JSR FRS1

 BCC FR1                \ If FRS1 returns with the C flag clear, then there
                        \ isn't room in the universe for our missile, so jump
                        \ down to FR1 to display a "missile jammed" message

 LDX MSTG               \ Fetch the slot number of the missile's target

 JSR GINF               \ Get the address of the data block for the target ship
                        \ and store it in INF

 LDA FRIN,X             \ Fetch the ship type of the missile's target into A

 JSR ANGRY              \ Call ANGRY to make the target ship hostile

 DEC NOMSL              \ Reduce the number of missiles we have by 1

 JSR msblob             \ Reset the dashboard's missile indicators so none of
                        \ them are targeted, returning with Y = 0 and X = &FF

 STY MSAR               \ The call to msblob returns Y = 0, so this sets MSAR
                        \ to 0 to indicate that the leftmost missile is no
                        \ longer seeking a target lock

 STX MSTG               \ The call to msblob returns X = &FF, so this resets the
                        \ missile so that it is no longer locked on a target

 JMP n_sound30          \ Call n_sound30 to make the sound of a missile launch,
                        \ returning from the subroutine using a tail call