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iigs-game-engine
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Fix off-by-one issue in tile IDs and make the entry point consistent in the code field generator

This commit is contained in:
Lucas Scharenbroich 2021-10-07 18:33:06 -05:00
parent 4006f76c02
commit d5421afdbd
2 changed files with 150 additions and 135 deletions
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105
demos/shell/gen/App.TileSetAnim.s
View File

@ -1,52 +1,65 @@
TileAnimInit ENT
TileAnimInit ENT
ldx #168
ldy #0
jsl CopyTileToDyn
ldx #169
ldy #1
jsl CopyTileToDyn
ldx #208
ldy #2
jsl CopyTileToDyn
ldx #209
ldy #3
jsl CopyTileToDyn
lda #TileAnim_168
ldx #^TileAnim_168
ldy #15
jsl StartScript
lda #TileAnim_169
ldx #^TileAnim_169
ldy #15
jsl StartScript
lda #TileAnim_208
ldx #^TileAnim_208
ldy #15
jsl StartScript
lda #TileAnim_209
ldx #^TileAnim_209
ldy #15
jsl StartScript
rts
ldx #168
ldy #0
jsl CopyTileToDyn
ldx #169
ldy #1
jsl CopyTileToDyn
ldx #208
ldy #2
jsl CopyTileToDyn
ldx #209
ldy #3
jsl CopyTileToDyn
lda #TileAnim_168 ; low word of handler
ldx #^TileAnim_168 ; high word of handler
ldy #15 ; number of ticks
jsl StartScript
lda #TileAnim_169
ldx #^TileAnim_169
ldy #15
clc
jsl StartScript
lda #TileAnim_208
ldx #^TileAnim_208
ldy #15
clc
jsl StartScript
lda #TileAnim_209
ldx #^TileAnim_209
ldy #15
clc
jsl StartScript
rts
TileAnim_168
dw $8006,168,0,0
dw $8006,170,0,0
dw $8006,172,0,0
dw $cd06,174,0,0
dw $8006,169,0,0
dw $8006,171,0,0
dw $8006,173,0,0
dw $cd06,175,0,0
TileAnim_169
dw $8006,169,1,0
dw $8006,171,1,0
dw $8006,173,1,0
dw $cd06,175,1,0
dw $8006,170,1,0
dw $8006,172,1,0
dw $8006,174,1,0
dw $cd06,176,1,0
TileAnim_208
dw $8006,208,2,0
dw $8006,210,2,0
dw $8006,212,2,0
dw $cd06,214,2,0
dw $8006,209,2,0
dw $8006,211,2,0
dw $8006,213,2,0
dw $cd06,215,2,0
TileAnim_209
dw $8006,209,3,0
dw $8006,211,3,0
dw $8006,213,3,0
dw $cd06,215,3,0
dw $8006,210,3,0
dw $8006,212,3,0
dw $8006,214,3,0
dw $cd06,216,3,0

180
src/blitter/Template.s
View File

@ -2,24 +2,24 @@
mx %00
DP_ADDR equ entry_1-base+1 ; offset to patch in the direct page for dynamic tiles
BG1_ADDR equ entry_2-base+1 ; offset to patch in the Y-reg for BG1 (dp),y addressing
STK_ADDR equ entry_3-base+1 ; offset to patch in the stack (SHR) right edge address
DP_ADDR equ entry_1-base+1 ; offset to patch in the direct page for dynamic tiles
BG1_ADDR equ entry_2-base+1 ; offset to patch in the Y-reg for BG1 (dp),y addressing
STK_ADDR equ entry_3-base+1 ; offset to patch in the stack (SHR) right edge address
DP_ENTRY equ entry_1-base
TWO_LYR_ENTRY equ entry_2-base
ONE_LYR_ENTRY equ entry_3-base
CODE_ENTRY_OPCODE equ entry_jmp-base
CODE_ENTRY equ entry_jmp-base+1 ; low byte of the page-aligned jump address
CODE_ENTRY equ entry_jmp-base+1 ; low byte of the page-aligned jump address
ODD_ENTRY equ odd_entry-base+1
CODE_TOP equ loop-base
CODE_LEN equ top-base
CODE_EXIT equ even_exit-base
OPCODE_SAVE equ odd_save-base ; spot to save the code field opcode when patching exit BRA
OPCODE_HIGH_SAVE equ odd_save-base+2 ; save the third byte
FULL_RETURN equ full_return-base ; offset that returns from the blitter
ENABLE_INT equ enable_int-base ; offset that re-enable interrupts and continues
OPCODE_SAVE equ odd_save-base ; spot to save the code field opcode when patching exit BRA
OPCODE_HIGH_SAVE equ odd_save-base+2 ; save the third byte
FULL_RETURN equ full_return-base ; offset that returns from the blitter
ENABLE_INT equ enable_int-base ; offset that re-enable interrupts and continues
LINES_PER_BANK equ 16
SNIPPET_BASE equ snippets-base
@ -64,17 +64,17 @@ BankPatchNum equ *-BankPatches
; usually only be executed once during app initialization. It doesn't get called
; with any significant frequency.
SetScreenRect sty ScreenHeight ; Save the screen height and width
SetScreenRect sty ScreenHeight ; Save the screen height and width
stx ScreenWidth
tax ; Temp save of the accumulator
tax ; Temp save of the accumulator
and #$00FF
sta ScreenY0
clc
adc ScreenHeight
sta ScreenY1
txa ; Restore the accumulator
txa ; Restore the accumulator
xba
and #$00FF
sta ScreenX0
@ -82,31 +82,31 @@ SetScreenRect sty ScreenHeight ; Save the screen height
adc ScreenWidth
sta ScreenX1
lda ScreenHeight ; Divide the height in scanlines by 8 to get the number tiles
lda ScreenHeight ; Divide the height in scanlines by 8 to get the number tiles
lsr
lsr
lsr
sta ScreenTileHeight
lda ScreenWidth ; Divide width in bytes by 4 to get the number of tiles
lda ScreenWidth ; Divide width in bytes by 4 to get the number of tiles
lsr
lsr
sta ScreenTileWidth
lda ScreenY0 ; Calculate the address of the first byte
asl ; of the right side of the playfield
lda ScreenY0 ; Calculate the address of the first byte
asl ; of the right side of the playfield
tax
lda ScreenAddr,x ; This is the address for the left edge of the physical screen
lda ScreenAddr,x ; This is the address for the left edge of the physical screen
clc
adc ScreenX1
dec
pha ; Save for second loop
pha ; Save for second loop
ldx #0
ldy ScreenHeight
jsr :loop
pla ; Reset the address and continue filling in the
ldy ScreenHeight ; second half of the table
pla ; Reset the address and continue filling in the
ldy ScreenHeight ; second half of the table
:loop clc
sta RTable,x
adc #160
@ -135,7 +135,7 @@ FillScreen lda #0
lsr
tay
lda #$FFFF
:xloop stal $E10000,x ; X is the absolute address
:xloop stal $E10000,x ; X is the absolute address
inx
inx
dey
@ -247,7 +247,7 @@ Mod208 cmp #%1101000000000000
; A = value
;
; Set M to 0 or 1
SetConst ; Need a blank line here, otherwise the :tbl local variable resolveds backwards
SetConst ; Need a blank line here, otherwise the :tbl local variable resolveds backwards
jmp (:tbl,x)
:tbl da :bottom-00,:bottom-03,:bottom-06,:bottom-09
da :bottom-12,:bottom-15,:bottom-18,:bottom-21
@ -381,13 +381,13 @@ BuildBank
lda [:bankArray],y
sta :target+2
iny ; move to the next item
iny ; move to the next item
iny
iny ; middle byte
cpy #4*13 ; if greater than the array length, wrap back to zero
iny ; middle byte
cpy #4*13 ; if greater than the array length, wrap back to zero
bcc :ok
ldy #1
:ok lda [:bankArray],y ; Get the middle and high bytes of the address
:ok lda [:bankArray],y ; Get the middle and high bytes of the address
sta :nextBank
:next
@ -406,7 +406,7 @@ BuildBank
; Change the patched value to one of DP_ENTRY, TWO_LYR_ENTRY or ONE_LYR_ENTRY based on the capabilities
; that the engine needs.
lda #$F000+{DP_ENTRY} ; Set the address from each line to the next
lda #$F000+{DP_ENTRY} ; Set the address from each line to the next
ldy #CODE_EXIT+1
ldx #15*2
jsr SetAbsAddrs
@ -414,14 +414,14 @@ BuildBank
ldy #DP_ADDR
jsr SetDPAddrs
ldy #$F000+CODE_EXIT ; Patch the last line with a JML to go to the next bank
lda #{$005C+{TWO_LYR_ENTRY}*256}
ldy #$F000+CODE_EXIT ; Patch the last line with a JML to go to the next bank
lda #{$005C+{DP_ENTRY}*256}
sta [:target],y
ldy #$F000+CODE_EXIT+2
lda :nextBank
sta [:target],y
ldy #$8000+CODE_EXIT ; Patch one line per bank to enable interrupts
ldy #$8000+CODE_EXIT ; Patch one line per bank to enable interrupts
lda #{$004C+{ENABLE_INT}*256}
sta [:target],y
@ -438,7 +438,7 @@ BuildBank
sta :target+2
:BuildLine2
lda #CODE_LEN ; round up to an even number of bytes
lda #CODE_LEN ; round up to an even number of bytes
inc
and #$FFFE
beq :nocopy
@ -452,11 +452,11 @@ BuildBank
dey
bpl :loop
:nocopy lda #0 ; copy is complete, now patch up the addresses
:nocopy lda #0 ; copy is complete, now patch up the addresses
sep #$20
ldx #0
lda :target+2 ; patch in the bank for the absolute long addressing mode
lda :target+2 ; patch in the bank for the absolute long addressing mode
:dobank ldy BankPatches,x
sta [:target],y
inx
@ -465,7 +465,7 @@ BuildBank
bcc :dobank
ldx #0
:dopage ldy PagePatches,x ; patch the page addresses by adding the page offset to each
:dopage ldy PagePatches,x ; patch the page addresses by adding the page offset to each
lda [:target],y
clc
adc :target+1
@ -485,71 +485,71 @@ BuildBank
;
; The 'base' location is always assumed to be on a 4kb ($1000) boundary
base
entry_1 ldx #0000 ; Used for LDA 00,x addressing
entry_2 ldy #0000 ; Used for LDA (00),y addressing
entry_3 lda #0000 ; Sets screen address (right edge)
entry_1 ldx #0000 ; Used for LDA 00,x addressing
entry_2 ldy #0000 ; Used for LDA (00),y addressing
entry_3 lda #0000 ; Sets screen address (right edge)
tcs
long_0
entry_jmp jmp $0100
dfb $00 ; if the screen is odd-aligned, then the opcode is set to
; $AF to convert to a LDA long instruction. This puts the
; first two bytes of the instruction field in the accumulator
; and falls through to the next instruction.
dfb $00 ; if the screen is odd-aligned, then the opcode is set to
; $AF to convert to a LDA long instruction. This puts the
; first two bytes of the instruction field in the accumulator
; and falls through to the next instruction.
; We structure the line so that the entry point only needs to
; update the low-byte of the address, the means it takes only
; an amortized 4-cycles per line to set the entry point break
; We structure the line so that the entry point only needs to
; update the low-byte of the address, the means it takes only
; an amortized 4-cycles per line to set the entry point break
right_odd bit #$000B ; Check the bottom nibble to quickly identify a PEA instruction
beq r_is_pea ; This costs 6 cycles in the fast-path
right_odd bit #$000B ; Check the bottom nibble to quickly identify a PEA instruction
beq r_is_pea ; This costs 6 cycles in the fast-path
bit #$0040 ; Check bit 6 to distinguish between JMP and all of the LDA variants
bit #$0040 ; Check bit 6 to distinguish between JMP and all of the LDA variants
bne r_is_jmp
long_1 stal *+4-base ; Everything else is a two-byte LDA opcode + PHA
long_1 stal *+4-base ; Everything else is a two-byte LDA opcode + PHA
dfb $00,$00
bra r_jmp_rtn
r_is_pea xba ; fast code for PEA
r_jmp_rtn sep #$20 ; shared return code path by all methods
r_is_pea xba ; fast code for PEA
r_jmp_rtn sep #$20 ; shared return code path by all methods
pha
rep #$20
odd_entry jmp $0100 ; unconditionally jump into the "next" instruction in the
; code field. This is OK, even if the entry point was the
; last instruction, because there is a JMP at the end of
; the code field, so the code will simply jump to that
; instruction directly.
;
; As with the original entry point, because all of the
; code field is page-aligned, only the low byte needs to
; be updated when the scroll position changes
odd_entry jmp $0100 ; unconditionally jump into the "next" instruction in the
; code field. This is OK, even if the entry point was the
; last instruction, because there is a JMP at the end of
; the code field, so the code will simply jump to that
; instruction directly.
;
; As with the original entry point, because all of the
; code field is page-aligned, only the low byte needs to
; be updated when the scroll position changes
r_is_jmp sep #$41 ; Set the C and V flags which tells a snippet to push only the low byte
r_is_jmp sep #$41 ; Set the C and V flags which tells a snippet to push only the low byte
long_2 ldal entry_jmp+1-base
long_3 stal *+5-base
jmp $0000 ; Jumps into the exception code, which returns to r_jmp_rtn
jmp $0000 ; Jumps into the exception code, which returns to r_jmp_rtn
; The next labels are special, in that they are entry points into special subroutines. They are special
; because they are within the first 256 bytes of each code field, which allows them to be selectable
; by patching the low byte of the JMP instructions.
; Return to caller -- the even_exit JMP from the previous line will jump here when a render is complete
full_return jml blt_return ; Full exit
full_return jml blt_return ; Full exit
; Re-enable interrupts and continue -- the even_exit JMP from the previous line will jump here every
; 8 or 16 lines in order to give the system some extra time to handle interrupts.
enable_int ldal stk_save+1 ; restore the stack
enable_int ldal stk_save+1 ; restore the stack
tcs
sep #$20 ; 8-bit mode
ldal STATE_REG ; Read Bank 0 / Write Bank 0
sep #$20 ; 8-bit mode
ldal STATE_REG ; Read Bank 0 / Write Bank 0
and #$CF
stal STATE_REG
cli
nop ; Give a couple of cycles
nop ; Give a couple of cycles
sei
ldal STATE_REG
ora #$10 ; Read Bank 0 / Write Bank 1
ora #$10 ; Read Bank 0 / Write Bank 1
stal STATE_REG
rep #$20
bra entry_1
@ -561,14 +561,14 @@ enable_int ldal stk_save+1 ; restore the stack
; page-crossing penalty of the branch.
ds 166
loop_exit_1 jmp odd_exit-base ; +0 Alternate exit point depending on whether the left edge is
loop_exit_2 jmp even_exit-base ; +3 odd-aligned
loop_exit_1 jmp odd_exit-base ; +0 Alternate exit point depending on whether the left edge is
loop_exit_2 jmp even_exit-base ; +3 odd-aligned
loop lup 82 ; +6 Set up 82 PEA instructions, which is 328 pixels and consumes 246 bytes
pea $0000 ; This is 41 8x8 tiles in width. Need to have N+1 tiles for screen overlap
loop lup 82 ; +6 Set up 82 PEA instructions, which is 328 pixels and consumes 246 bytes
pea $0000 ; This is 41 8x8 tiles in width. Need to have N+1 tiles for screen overlap
--^
loop_back jmp loop-base ; +252 Ensure execution continues to loop around
loop_exit_3 jmp even_exit-base ; +255
loop_back jmp loop-base ; +252 Ensure execution continues to loop around
loop_exit_3 jmp even_exit-base ; +255
long_5
odd_exit ldal l_is_jmp+1-base
@ -576,7 +576,7 @@ odd_exit ldal l_is_jmp+1-base
bne :chk_jmp
sep #$20
long_6 ldal l_is_jmp+3-base ; get the high byte of the PEA operand
long_6 ldal l_is_jmp+3-base ; get the high byte of the PEA operand
; Fall-through when we have to push a byte on the left edge. Must be 8-bit on entry. Optimized
; for the PEA $0000 case -- only 19 cycles to handle the edge, so pretty good
@ -585,8 +585,8 @@ long_6 ldal l_is_jmp+3-base ; get the high byte of th
rep #$20
; JMP opcode = $4C, JML opcode = $5C
even_exit jmp $1000 ; Jump to the next line.
ds 1 ; space so that the last line in a bank can be patched into a JML
even_exit jmp $1000 ; Jump to the next line.
ds 1 ; space so that the last line in a bank can be patched into a JML
:chk_jmp
bit #$0040
@ -600,8 +600,8 @@ l_jmp_rtn xba
rep #$20
bra even_exit
l_is_jmp sec ; Set the C flag (V is always cleared at this point) which tells a snippet to push only the high byte
odd_save dfb $00,$00,$00 ; The odd exit 3-byte sequence is always stashed here
l_is_jmp sec ; Set the C flag (V is always cleared at this point) which tells a snippet to push only the high byte
odd_save dfb $00,$00,$00 ; The odd exit 3-byte sequence is always stashed here
; Special epilogue: skip a number of bytes and jump back into the code field. This is useful for
; large, floating panels in the attract mode of a game, or to overlay solid
@ -611,8 +611,8 @@ epilogue_1 tsc
sec
sbc #0
tcs
jmp $0000 ; This jumps back into the code field
:out jmp $0000 ; This jumps to the next epilogue chain element
jmp $0000 ; This jumps back into the code field
:out jmp $0000 ; This jumps to the next epilogue chain element
ds 1
; These are the special code snippets -- there is a 1:1 relationship between each snippet space
@ -667,21 +667,21 @@ epilogue_1 tsc
; ...
ds \,$00 ; pad to the next page boundary
ds \,$00 ; pad to the next page boundary
]index equ 0
snippets lup 82
ds 2 ; space for a 2-byte sequence; LDA (00),y LDA 00,x LDA 0,s
and #$0000 ; the mask operand will be set when the tile is drawn
ora #$0000 ; the data operand will be set when the tile is drawn
ds 2 ; space for a 2-byte sequence; LDA (00),y LDA 00,x LDA 0,s
and #$0000 ; the mask operand will be set when the tile is drawn
ora #$0000 ; the data operand will be set when the tile is drawn
bcs *+6
pha
brl loop+3+{3*]index} ; use relative branch for convenience
bvs *+6 ; overflow set means this is the right edge (entry)
clc ; carry is set only for edge operations; force clear
brl loop+3+{3*]index} ; use relative branch for convenience
bvs *+6 ; overflow set means this is the right edge (entry)
clc ; carry is set only for edge operations; force clear
brl l_jmp_rtn
rep #$41 ; clear V and C
brl r_jmp_rtn ; 25 bytes
ds 7 ; padding
rep #$41 ; clear V and C
brl r_jmp_rtn ; 25 bytes
ds 7 ; padding
]index equ ]index+1
--^
top
@ -693,3 +693,5 @@ top