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Elite on the BBC Micro

Sound: TALK (6502SP version)

Name: TALK [View in context] Type: Subroutine [Compare versions] Category: Sound Summary: Speak using the Watford Electronics Beeb Speech Synthesiser Deep dive: Secrets of the Executive version
In the Executive version, if you have a Watford Electronics Beeb Speech Synthesiser fitted and enable speech by presing ":" while the game is paused, then the game will speak to you at various points. Arguments: X The number of the phrase to speak: 1 = "Incoming missile" 2 = "Energy low" 3 = "Elite" 4 = "Oh shit, it's a mis-jump"
.TALK IF _EXECUTIVE TYA \ Store Y on the stack to we can retrieve it later PHA BIT SPEAK \ If SPEAK is 0, then speech is not enabled, so jump BPL TALK4 \ to TALK4 to restore Y from the stack and return \ from the subroutine LDA #0 \ Set SC = 0 STA SC LDY #LO(SPEECH) \ Set Y to point to the low byte of SPEECH LDA #HI(SPEECH) \ Set SC(1 0) so it points to the start of the page STA SC+1 \ containing SPEECH, so by this point, so SC+Y points \ to the first byte of SPEECH .TALKL LDA (SC),Y \ Fetch the next byte from the SPEECH block CMP #13 \ If it not 13 (which is the terminator for each speech BNE TALK1 \ command), jump to TALK1 to skip to the next byte DEX \ We just reached a terminator, so decrement the phrase \ number in X BEQ TALK2 \ If X is now 0, we have now found the terminator just \ before the phrase we want (the X-th phrase), so jump \ to TALK2 to speak it .TALK1 INY \ Increment the byte counter in Y to point to the next \ byte in the SPEECH table BNE TALKL \ If Y is non-zero, loop back to TALKL to process the \ next byte INC SC+1 \ Y is 0, which means SC+Y has just crossed a page \ boundary, so increment the high byte in SC+1 so that \ SC+Y points to the next page BNE TALKL \ Loop back to TALKL to process the next byte (this BNE \ is effectively a JMP as SC+1 is never zero) .TALK2 INY \ If we get here then SC+Y points to the terminator \ before the phrase we want, so increment Y to point to \ the start of the phrase we want BNE TALK3 \ If Y is non-zero, then SC+Y points to the phrase we \ want to speak, so jump to TALK3 to do the speaking INC SC+1 \ Y is 0, which means SC+Y has just crossed a page \ boundary, so increment the high byte in SC+1 so that \ SC+Y points to the next page .TALK3 TYA \ Set (Y X) to point to (SC+1 Y), i.e. SC+Y TAX LDY SC+1 JSR OSCLI \ Call OSCLI to run the OS command in SC+Y, which will \ be of the form "*TALK xx", a command for making the \ Watford Electronics Beeb Speech Synthesiser talk .TALK4 PLA \ Restore the value of Y we stored on the stack, so it TAY \ gets preserved across the call to the subroutine RTS \ Return from the subroutine ENDIF