Add new N-SPC commands FA (mute) and FB (unmute)

spc.asm

@@ -0,0 +1,41 @@
+;=======================================
+; SPC engine changes
+;
+; Free space at $040F-07FF (probably)
+;
+; If we ever switch to ASAR we can rewrite
+; this as actual SPC asm instead of this
+; db jank.
+
+; seek($0700)
+db $68, $F0         ; CMP A,#$F0            ; the thing we overwrote
+db $D0, $03         ; BNE +
+db $5F, $81, $0A    ;   JMP SilenceSong     ; ($0A81)
+db $68, $FA         ; + : CMP A,#$FA        ; new mute command $FA
+db $D0, $21         ; BNE +
+db $E8, $00         ;   MOV A,#$00
+db $C5, $4A, $0A    ;   MOV $0A4A,A         ; $0A49: MOV A,#$70 -> MOV A,#$00
+db $C5, $F3, $0A    ;   MOV $0AF3,A         ; $0AF2: MOV $059,#$C0 -> MOV $059,#$00
+db $C5, $32, $0C    ;   MOV $0C32,A         ; $0C32: MOVW $058,YA -> NOP #2
+db $C5, $33, $0C    ;   MOV $0C33,A
+db $E8, $C4         ;   MOV A,#$C4          ; $0D19: MOVW $058,YA -> MOV $058,A
+db $C5, $19, $0D    ;   MOV $0D19,A
+db $E8, $58         ;   MOV A,#$58
+db $C5, $1A, $0D    ;   MOV $0D1A,A
+db $3F, $81, $0A    ; - : CALL SilenceSong  ; ($0A81)
+db $FA, $00, $04    ;   MOV $04, $00
+db $5F, $00, $0B    ;   JMP No_New_Song     ; ($0B00)
+db $68, $FB         ; + : CMP A,#$FB        ; new unmute command $FB
+db $F0, $03         ; BEQ +
+db $5F, $9D, $0A    ;   JMP NewSongInput    ; ($0A9D)
+db $E8, $70         ; + : MOV A,#$70
+db $C5, $4A, $0A    ; MOV $0A4A,A           ; $0A49: MOV A,#$70
+db $E8, $C0         ; MOV A,#$C0
+db $C5, $F3, $0A    ; MOV $0AF3,A           ; $0AF2: MOV $059,#$C0
+db $E8, $DA         ; MOV A,#$DA
+db $C5, $32, $0C    ; MOV $0C32,A           ; $0C32: MOVW $058,YA
+db $C5, $19, $0D    ; MOV $0D19,A           ; $0D19: MOVW $058,YA
+db $E8, $58         ; MOV A,#$58
+db $C5, $33, $0C    ; MOV $0C33,A
+db $C5, $1A, $0D    ; MOV $0D1A,A
+db $2F, $D4         ; BRA -