Now with pausing and other niceties

5 files changed, 260 insertions, 145 deletions

diff --git a/src-z80/core/bgm.z80 b/src-z80/core/bgm.z80
index 338a7a6..b48d87a 100644
--- a/src-z80/core/bgm.z80
+++ b/src-z80/core/bgm.z80
@@ -25,13 +25,14 @@ PlayBGM:
 
     PollPCM
 
-    xor a                       ; Command parsed
-    ld (RAM_Command), a
+    xor a                       ; Playing a BGM immediately unpauses playback
+    ld (RAM_Paused), a
 
+    inc a
     ld hl, RAM_BGMData          ; Set BGM as playing
-    ld (hl), $01
+    ld (hl), a
     inc l                       ; No delays!
-    ld (hl), $01
+    ld (hl), a
     inc l                       ; Store BGM start bank
     ld (hl), c
     inc l                       ; Store BGM start address (low)
@@ -44,55 +45,111 @@ PlayBGM:
     ld hl, ProcessBGM           ; Tell Echo to process BGM
     ld (DoTick_BGM+1), hl
     
-    jp IdleLoop                 ; End of subroutine
+    jp EndOfCommand             ; End of subroutine
 
 ;****************************************************************************
-; ResumeBGM [command $06]
-; Resumes a stopped BGM
+; PauseBGM [command $08]
+; Pauses a playing BGM
 ;----------------------------------------------------------------------------
 ; breaks: all
 ;****************************************************************************
 
-ResumeBGM:
-    xor a                       ; Command parsed
-    ld (RAM_Command), a
+PauseBGM:
+    ld a, (RAM_BGMPlaying)      ; Is BGM even playing?
+    or a
+    jp z, EndOfCommand
+    
+    ld a, 1                     ; Halt BGM playback
+    ld (RAM_Paused), a
 
 ;----------------------------------------------------------------------------
-    
-    ld b, 8                     ; Restore all FM channels
-    ld de, RAM_Locked+7
-.restorefm:
 
+    ld b, $7F                   ; Mute all FM channels
+    ld c, 7
+    ld hl, RAM_Locked+7
+.mutefm:
     PollPCM
-
-    ld a, (de)                    ; Check if this channel is locked
+    ld a, (hl)
     or a
-    jp nz, .fmlocked
-
+    jr nz, .nofmmute
+    ld a, c
+    call SetFMVolTempLoad
+.nofmmute:
     PollPCM
+    dec l
+    dec c
+    jp p, .mutefm
     
-    dec b                         ; Restore FM channel
-    call RestoreFM
-    inc b
-    
-.fmlocked:
-    dec e                         ; Go for next channel to restore
-    dec b
-    jp nz, .restorefm
+    ld b, 4                     ; Mute all PSG channels
+    ld c, $0F
+    ld de, RAM_Locked+8
+    ld hl, RAM_PSGData
+.mutepsg:
+    PollPCM
+    ld a, (de)
+    or a
+    jr nz, .nopsgmute
+    ld a, (hl)
+    and $80
+    or c,
+    ld (hl), a
+.nopsgmute:
+    PollPCM
+    ld a, l
+    add 16
+    ld l, a
+    inc e
+    djnz .mutepsg
 
 ;----------------------------------------------------------------------------
 
-    ld a, (RAM_Status)          ; Show BGM playback in Echo's status
-    or $02
-    ld (RAM_Status), a
+    ld a, (RAM_Locked+6)        ; Mute PCM channel
+    or a
+    call z, StopPCM
 
-    ld hl, RAM_BGMData          ; Set BGM as playing
-    ld (hl), $01
+;----------------------------------------------------------------------------
+
+    jp EndOfCommand             ; End of subroutine
+
+;****************************************************************************
+; ResumeBGM [command $06]
+; Resumes a stopped BGM
+;----------------------------------------------------------------------------
+; breaks: all
+;****************************************************************************
+
+ResumeBGM:
+    ld a, (RAM_BGMPlaying)      ; Was BGM even playing?
+    or a
+    jp z, EndOfCommand
     
-    ld hl, ProcessBGM           ; Tell Echo to process BGM
-    ld (DoTick_BGM+1), hl
+    xor a
+    ld (RAM_Paused), a          ; Resume BGM playback
     
-    jp IdleLoop                 ; End of subroutine
+    ld b, 4                     ; Restore PSG channels
+    ld de, RAM_Locked+11
+    ld hl, RAM_PSGData+63
+.resumepsg:
+    PollPCM
+    ld c, (hl)
+    ld a, l
+    sub 15
+    ld l, a
+    ld a, (de)
+    or a
+    jr nz, .nopsgresume
+    ld a, (hl)
+    and $80
+    or c
+    ld (hl), a
+.nopsgresume:
+    PollPCM
+    dec l
+    dec e
+    djnz .resumepsg
+    
+    call RefreshVolume          ; Restore remaining channels
+    jp EndOfCommand             ; End of subroutine
 
 ;****************************************************************************
 ; ProcessBGM
@@ -197,6 +254,9 @@ ProcessBGMEventFF:
     jp c, SetFMParamBGM
     cp $FA                      ; Events $F8-$F9: set FM register
     jp c, SetFMRegBGM
+    jp z, SetFlagsBGM           ; Events $FA-$FB: set/clear flags
+    cp $FB
+    jp z, ClearFlagsBGM
 
     PollPCM                     ; FFFFFFFFF bad event >:(
 ProcessBGMEnd:
@@ -234,10 +294,8 @@ StopBGMEvent:
     jp DoTick_BGMSkip           ; End of subroutine
 
 StopBGMCmd:
-    xor a                       ; Command parsed
-    ld (RAM_Command), a
     call StopBGM                ; We're just a wrapper
-    jp IdleLoop                 ; End of subroutine
+    jp EndOfCommand             ; End of subroutine
 
 StopBGM:
     ld a, (RAM_Status)          ; Hide BGM playback in Echo's status
@@ -271,7 +329,7 @@ ClearBGM:
     ld b, 4                     ; Reset all PSG channels
     ld de, RAM_PSGData+48+15
     ld hl, RAM_Locked+11
-.mutepsg:
+.killpsg:
     PollPCM
     
     ld (hl), $00                ; Reset BGM volume
@@ -282,22 +340,22 @@ ClearBGM:
     
     ld a, (hl)                  ; Mute PSG channel if it isn't locked
     or a
-    jr nz, .nopsgmute
+    jr nz, .nopsgkill
     xor a
     ld (de), a
     
-.nopsgmute:
+.nopsgkill:
     PollPCM
     
     dec e
     dec l
-    djnz .mutepsg
+    djnz .killpsg
 
 ;----------------------------------------------------------------------------
 
     ld b, 8                     ; Reset all FM channels
     ld de, RAM_BGMFMVol+7
-.resetfm:
+.killfm:
     PollPCM
     
     ld a, $7F                   ; Reset BGM volume
@@ -328,10 +386,10 @@ ClearBGM:
     inc b
 .nofmkill:
     dec l
-    djnz .resetfm
+    djnz .killfm
 
 ;----------------------------------------------------------------------------
-    
+
     ld hl, RAM_BGMFMPan         ; Reset panning status (for restoring)
     ld a, $C0
     ld b, 8
@@ -339,6 +397,9 @@ ClearBGM:
     ld (hl), a
     inc l
     djnz .initpanstat
+    
+    xor a                       ; Reset flags
+    ld (RAM_Flags), a
 
     ret                         ; End of subroutine
 
@@ -349,19 +410,11 @@ ClearBGM:
 
 LoopBGM:
     PollPCM
-
-    ex de, hl                   ; Get looping address
-    inc l
-    ld c, (hl)
-    inc l
-    ld e, (hl)
-    inc l
-    ld d, (hl)
-    dec l
-    dec l
-    dec l
-    ex de, hl
-
+    
+    ld hl, (RAM_BGMLoopPoint+1) ; Get looping address
+    ld a, (RAM_BGMLoopPoint)
+    ld c, a
+    
     jp ProcessBGMRun            ; End of subroutine
 
 ;****************************************************************************
@@ -371,17 +424,9 @@ LoopBGM:
 
 SetLoopBGM:
     PollPCM
-
-    ex de, hl
-    inc l                       ; Store loop point address
-    ld (hl), c
-    inc l
-    ld (hl), e
-    inc l
-    ld (hl), d
-    dec l
-    dec l
-    dec l
-    ex de, hl
-
+    
+    ld a, c                     ; Store loop point address
+    ld (RAM_BGMLoopPoint), a
+    ld (RAM_BGMLoopPoint+1), hl
+    
     jp ProcessBGMRun            ; End of subroutine
diff --git a/src-z80/core/macro.z80 b/src-z80/core/macro.z80
new file mode 100644
index 0000000..eedd527
--- /dev/null
+++ b/src-z80/core/macro.z80
@@ -0,0 +1,41 @@
+;****************************************************************************
+; PollPCM
+; Used to update PCM while not idle
+;----------------------------------------------------------------------------
+; breaks: af
+;****************************************************************************
+
+PollPCM: macro
+    ld a, ($4000)
+    rrca
+    rst $08
+    endm
+
+;****************************************************************************
+; BankSwitch
+; Switches into a new bank (won't update player status!)
+;----------------------------------------------------------------------------
+; input A .... New bank to switch into
+; input HL ... Must be $60xx
+;----------------------------------------------------------------------------
+; breaks ..... AF
+;****************************************************************************
+
+BankSwitch: macro
+    ld (hl), a
+    rrca
+    ld (hl), a
+    rrca
+    ld (hl), a
+    rrca
+    ld (hl), a
+    rrca
+    ld (hl), a
+    rrca
+    ld (hl), a
+    rrca
+    ld (hl), a
+    ld (hl), h
+    rrca
+    ld (hl), a
+    endm
diff --git a/src-z80/core/main.z80 b/src-z80/core/main.z80
index 4eb6e5a..387b879 100644
--- a/src-z80/core/main.z80
+++ b/src-z80/core/main.z80
@@ -4,10 +4,11 @@
 ;****************************************************************************
 
 EntryPoint:
-    ld sp, RAM_Stack            ; Init stack
+    xor a                       ; Reset Echo status (we don't clear
+    ld (RAM_Status), a          ; RAM_Command since Echo_Init fills in values
+    ld (RAM_Command2), a        ; before Echo gets to run!)
 
-    xor a                       ; Reset Echo status
-    ld (RAM_Status), a
+    ld sp, RAM_Stack            ; Init stack
 
     ld hl, $7F11                ; Mute PSG
     ld (hl), $9F
@@ -88,22 +89,11 @@ EntryPoint:
     jp IdleLoop                 ; Go into idle loop
 
 ;****************************************************************************
-; PollPCM
-; Used to update PCM while not idle
-;----------------------------------------------------------------------------
-; breaks: af
-;****************************************************************************
-
-PollPCM: macro
-    ld a, ($4000)
-    rrca
-    call c, UpdatePCM
-    endm
-
-;****************************************************************************
 ; RunCommand
 ; Checks which command to run
 ;----------------------------------------------------------------------------
+; notes: doesn't return
+;----------------------------------------------------------------------------
 ; To-do: replace with pointer list?
 ;****************************************************************************
 
@@ -122,17 +112,36 @@ RunCommand:
     jp z, ResumeBGM
     dec a                       ; Command $07: set PCM rate
     jp z, SetPCMRate
+    dec a                       ; Command $08: pause BGM
+    jp z, PauseBGM
 
     PollPCM
 
-    xor a                       ; Bad command, ignore >:(
-    ld (RAM_Command), a
+    ; Bad command, ignore >:(
+
+;****************************************************************************
+; EndOfCommand
+; Cleans up when a command finishes
+;----------------------------------------------------------------------------
+; notes: doesn't return
+;****************************************************************************
 
+EndOfCommand:
+    ld hl, ($1FF8)              ; Copy second slot into first
+    ld ($1FFC), hl
+    ld hl, ($1FFA)
+    ld ($1FFE), hl
+    
+    xor a                       ; Free up second slot
+    ld (RAM_Command2), a
+    
     PollPCM
 
 ;****************************************************************************
 ; IdleLoop
 ; Loop that runs when not processing SFX or BGM
+;----------------------------------------------------------------------------
+; notes: doesn't return (d'oh)
 ;****************************************************************************
 
 IdleLoop:
@@ -153,13 +162,11 @@ IdleLoop:
 ;****************************************************************************
 ; DoTick
 ; Called whenever a new tick triggers
+;----------------------------------------------------------------------------
+; notes: doesn't return
 ;****************************************************************************
 
 DoTick:
-;    ld a, (ix+0)
-;    bit 0, a
-;    call nz, UpdatePCM
-
     PollPCM
 
     ld (ix+0), $27              ; Retrigger the timer
@@ -181,6 +188,9 @@ DoTick_SFXSkip:
 
     PollPCM
     
+    ld a, (RAM_Paused)          ; BGMs are paused?
+    or a
+    jr nz, DoTick_BGMSkip
 DoTick_BGM:                     ; Process BGMs
     jp DoTick_BGMSkip
 DoTick_BGMSkip:
@@ -195,57 +205,30 @@ DoTick_PSGSkip:
     jp IdleLoop                 ; End of subroutine
 
 ;****************************************************************************
-; BankSwitch
-; Switches into a new bank (won't update player status!)
-;
-; input A .... New bank to switch into
-; input HL ... Must be $6000
-; breaks ..... AF
-;****************************************************************************
-
-BankSwitch: macro
-    ld (hl), a
-    rrca
-    ld (hl), a
-    rrca
-    ld (hl), a
-    rrca
-    ld (hl), a
-    rrca
-    ld (hl), a
-    rrca
-    ld (hl), a
-    rrca
-    ld (hl), a
-    ld (hl), h
-    rrca
-    ld (hl), a
-    endm
-
-;****************************************************************************
 ; LoadList [command $01]
 ; Loads the pointer list
 ;****************************************************************************
 
 LoadList:
-    ld hl, RAM_ComBank          ; Get command parameters
-    ld c, (hl)
-    inc l
-    ld e, (hl)
-    inc l
-    ld d, (hl)
-    ex de, hl
-
-    xor a                       ; Command parsed
-    ld (RAM_Command), a
+;    ld hl, RAM_ComBank          ; Get command parameters
+;    ld c, (hl)
+;    inc l
+;    ld e, (hl)
+;    inc l
+;    ld d, (hl)
+;    ex de, hl
+    
+    ld hl, (RAM_ComAddr)        ; Get command parameters
+    ld a, (RAM_ComBank)
+    ld c, a
 
     ld de, RAM_PointerList      ; Where the pointer list starts
 
-.loop:
+.loadloop:
     call GetParam               ; Get high byte address
     ld a, b                     ; Is it the end of the list?
     or a
-    jp z, .end
+    jp z, .loadend
     ld (de), a                  ; Store high byte address
     inc d
     
@@ -261,10 +244,10 @@ LoadList:
     dec d                       ; Go for next byte
     dec d
     inc e
-    jp .loop
+    jp .loadloop
 
-.end:
-    jp IdleLoop                 ; End of subroutine
+.loadend:
+    jp EndOfCommand             ; End of subroutine
 
 ;****************************************************************************
 ; GetParam
diff --git a/src-z80/core/sfx.z80 b/src-z80/core/sfx.z80
index 4bca4c7..8c5e7dd 100644
--- a/src-z80/core/sfx.z80
+++ b/src-z80/core/sfx.z80
@@ -25,9 +25,6 @@ PlaySFX:
 
     PollPCM
 
-    xor a                       ; Command parsed
-    ld (RAM_Command), a
-
     ld hl, RAM_SFXData          ; Set SFX as playing
     ld (hl), $01
     inc l                       ; No delays!
@@ -45,7 +42,7 @@ PlaySFX:
     ld (DoTick_SFX+1), hl
 
     PollPCM
-    jp IdleLoop                 ; End of subroutine
+    jp EndOfCommand             ; End of subroutine
 
 ;****************************************************************************
 ; ProcessSFX
@@ -153,6 +150,14 @@ ProcessSFXRun:
     jp c, SetFMParamSFX
     cp $FA                      ; Events $F8-$F9: set FM register
     jp c, SetFMRegSFX
+    jp z, SetFlagsSFX           ; Events $FA-$FB: set/clear flags
+    cp $FB
+    jp z, ClearFlagsSFX
+    
+    cp $FC
+    jp z, LoopSFX               ; Event $FC: loop SFX
+    cp $FD
+    jp z, SetLoopSFX            ; Event $FD: set loop point
 
 ;****************************************************************************
 ; StopSFX* [command $03, event $FF]
@@ -166,10 +171,8 @@ StopSFXEvent:
     jp DoTick_SFXSkip           ; End of subroutine
 
 StopSFXCmd:
-    xor a                       ; Command parsed
-    ld (RAM_Command), a
     call StopSFX                ; We're just a wrapper
-    jp IdleLoop                 ; End of subroutine
+    jp EndOfCommand             ; End of subroutine
 
 StopSFX:
     PollPCM
@@ -283,9 +286,36 @@ ClearSFX:
     
 .fmfree:
     dec e                         ; Go for next FM channel to unlock
-    dec b
-    jp nz, .unlockfm
+    djnz .unlockfm
 
 ;----------------------------------------------------------------------------
 
     ret                         ; End of subroutine
+
+;****************************************************************************
+; LoopSFX [event $FC]
+; Makes a SFX loop
+;****************************************************************************
+
+LoopSFX:
+    PollPCM
+    
+    ld hl, (RAM_SFXLoopPoint+1) ; Get looping address
+    ld a, (RAM_SFXLoopPoint)
+    ld c, a
+    
+    jp ProcessSFXRun            ; End of subroutine
+
+;****************************************************************************
+; SetLoopSFX [event $FD]
+; Sets the SFX loop point
+;****************************************************************************
+
+SetLoopSFX:
+    PollPCM
+    
+    ld a, c                     ; Store loop point address
+    ld (RAM_SFXLoopPoint), a
+    ld (RAM_SFXLoopPoint+1), hl
+    
+    jp ProcessSFXRun            ; End of subroutine
diff --git a/src-z80/core/vars.z80 b/src-z80/core/vars.z80
index cd7162d..79e4a1d 100644
--- a/src-z80/core/vars.z80
+++ b/src-z80/core/vars.z80
@@ -42,13 +42,23 @@ RAM_SFXPlaying:     ds 1              ; Set if a SFX is playing
 RAM_SFXDelay:       ds 1              ; How many ticks to wait
 RAM_SFXBank:        ds 1              ; Current SFX bank
 RAM_SFXAddress:     ds 2              ; Current SFX address
+RAM_SFXLoopPoint:   ds 3              ; SFX loop point
+
+RAM_Paused:         ds 1            ; Set if BGM stream is paused
+
+RAM_PCMBank1:       db 1            ; (not implemented yet)
+RAM_PCMAddr1:       dw 1            ; (not implemented yet)
+RAM_PCMBank2:       db 1            ; (not implemented yet)
+RAM_PCMAddr2:       dw 1            ; (not implemented yet)
 
 RAM_Scratch:        ds 32           ; Scratch bytes, may be useful when
                                       ; buffering to speed up to avoid bank
                                       ; switching conflicts
 
     ds $F0-($&$FF), $FF
-RAM_PCMBuffer:      ds 16           ; PCM buffer
+RAM_PCMBuffer:      ds 0            ; PCM buffer
+RAM_PCMBuffer1:     ds 8            ; (not implemented yet)
+RAM_PCMBuffer2:     ds 8            ; (not implemented yet)
 
 ;****************************************************************************
 ; Pointer list starts being stored from here
@@ -71,6 +81,12 @@ RAM_Stack:          equ $1FE0       ; Where stack starts
 RAM_GlobalVol:      equ $1FE0       ; Global volume for all channels
 RAM_Status:         equ $1FF0       ; Current playback status
 RAM_RefreshVol:     equ $1FF1       ; Set to refresh all volumes
+RAM_Flags:          equ $1FF2       ; Track flags
+
 RAM_Command:        equ $1FFF       ; Command type
 RAM_ComAddr:        equ $1FFD       ; Command address parameter
 RAM_ComBank:        equ $1FFC       ; Command bank parameter
+
+RAM_Command2:       equ $1FFB       ; (second slot for all the above)
+RAM_ComAddr2:       equ $1FF9
+RAM_ComBank2:       equ $1FF8