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MMC1 512K PRG support #396

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28ab2c9
MMC1 512K PRG support
sebastienvezina Apr 28, 2025
17b9b48
Fixed double __ in register names
sebastienvezina Apr 28, 2025
88e2cb5
vscode plugin ignore - not needed
sebastienvezina Apr 28, 2025
a00393e
skip set CHR bits if switch to bank < 16
sebastienvezina Apr 28, 2025
9993ac2
fix switching to a high bank was exiting early in the middle of the b…
sebastienvezina Apr 28, 2025
d11ec30
replaced cmp/bne w and/beq
sebastienvezina Apr 28, 2025
085fec1
update actual registers
sebastienvezina Apr 28, 2025
659a4a0
nes-mmc1 prg 512 unit tests
sebastienvezina Apr 28, 2025
2610b30
hex to lowercase + removed references to prg 15
sebastienvezina Apr 28, 2025
cc334b9
jrowboy's set_prg_bank
sebastienvezina Apr 29, 2025
af1dc55
review https://github.com/llvm-mos/llvm-mos-sdk/pull/396#discussion_r…
sebastienvezina Apr 29, 2025
1661294
fix https://github.com/llvm-mos/llvm-mos-sdk/pull/396#discussion_r206…
sebastienvezina Apr 29, 2025
a93c409
fix https://github.com/llvm-mos/llvm-mos-sdk/pull/396#discussion_r206…
sebastienvezina Apr 29, 2025
48992f0
latest version of set_prg_bank but still use prg_rom_is_512 which sho…
sebastienvezina Apr 29, 2025
a1a1df2
attempt at fixing the fixed bank output format
sebastienvezina Apr 29, 2025
ed2856d
added __ prefix to prg_rom_is_512
sebastienvezina Apr 29, 2025
181ecda
try to preserve the PRG RAM bit
sebastienvezina Apr 29, 2025
500564c
Added prg-rom-512 test to list
sebastienvezina Apr 30, 2025
b62a60f
banked_call fiddling because set_prg_bank clobbers rc2 and/or rc3
sebastienvezina May 5, 2025
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65 changes: 51 additions & 14 deletions mos-platform/nes-mmc1/mapper.s
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Original file line number Diff line number Diff line change
Expand Up @@ -99,9 +99,39 @@ get_prg_bank:
.weak set_prg_bank
__set_prg_bank:
set_prg_bank:
tay
ldx #<__prg_rom_is_512
beq .Lcontinue_bank_switch
; save the new bank byte on the stack for safe keeping
pha
; check which bits changed
eor _PRG_BANK
; if the outer bank bit changed then we need to set a new outerbank
and #%00010000
beq .Lset_inner_bank
.Lset_new_outer_bank:
; Flip the outer bank bit for _CHR_BANK0 and _CHR_BANK1
lda _CHR_BANK0
eor #%00010000
jsr set_chr_bank_0_retry
lda _CHR_BANK1
eor #%00010000
jsr set_chr_bank_1_retry
.Lset_inner_bank:
; restore the bank byte and put it in y so we can reload it on retry
pla
.Lcontinue_bank_switch:
; bit 4 is PRG RAM en/disable, so use those from the current bank value
ldx __rc2 ; preserve the current __rc2 value in X so we can use it as a temp
and #%00001111
sta __rc2 ; store the new bank bits
lda _PRG_BANK ; load the current prg_ram enable bit
and #%00010000
ora __rc2 ; combine them together
stx __rc2 ; restore the tmp register we used
tay
; original code below
.Lset:
inc __reset_mmc1_byte
inc __reset_mmc1_byte
ldx #1
stx _IN_PROGRESS
mmc1_register_write MMC1_PRG
Expand All @@ -115,21 +145,28 @@ set_prg_bank:
tya
jmp .Lset



.section .text.banked_call,"ax",@progbits
.weak banked_call
banked_call:
tay
lda _PRG_BANK
pha
tya
jsr __set_prg_bank
lda __rc2
sta __rc18
lda __rc3
sta __rc19
tay ; save current bank in y
lda _PRG_BANK ; load new bank in A
pha ; push new bank to stack

lda __rc2 ; push function pointer to stack
pha
lda __rc3
pha

tya ; restore current bank from A

jsr __set_prg_bank ; set the new bank

pla ; restore function pointer from stack
sta __rc19
pla
sta __rc18

jsr __call_indir
pla
jsr __set_prg_bank
rts
rts
82 changes: 82 additions & 0 deletions mos-platform/nes-mmc1/prg-rom-banked.ld
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Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,21 @@ __prg_rom_11_lma = 0x0b8000;
__prg_rom_12_lma = 0x0c8000;
__prg_rom_13_lma = 0x0d8000;
__prg_rom_14_lma = 0x0e8000;
__prg_rom_16_lma = 0x108000;
__prg_rom_17_lma = 0x118000;
__prg_rom_18_lma = 0x128000;
__prg_rom_19_lma = 0x138000;
__prg_rom_20_lma = 0x148000;
__prg_rom_21_lma = 0x158000;
__prg_rom_22_lma = 0x168000;
__prg_rom_23_lma = 0x178000;
__prg_rom_24_lma = 0x188000;
__prg_rom_25_lma = 0x198000;
__prg_rom_26_lma = 0x1a8000;
__prg_rom_27_lma = 0x1b8000;
__prg_rom_28_lma = 0x1c8000;
__prg_rom_29_lma = 0x1d8000;
__prg_rom_30_lma = 0x1e8000;
__prg_rom_fixed_lma = 0xc000;

__prg_rom_0_offset = 0x00000;
Expand All @@ -32,6 +47,21 @@ __prg_rom_11_offset = 0x2c000;
__prg_rom_12_offset = 0x30000;
__prg_rom_13_offset = 0x34000;
__prg_rom_14_offset = 0x38000;
__prg_rom_16_offset = 0x40000;
__prg_rom_17_offset = 0x44000;
__prg_rom_18_offset = 0x48000;
__prg_rom_19_offset = 0x4c000;
__prg_rom_20_offset = 0x50000;
__prg_rom_21_offset = 0x54000;
__prg_rom_22_offset = 0x58000;
__prg_rom_23_offset = 0x5c000;
__prg_rom_24_offset = 0x60000;
__prg_rom_25_offset = 0x64000;
__prg_rom_26_offset = 0x68000;
__prg_rom_27_offset = 0x6c000;
__prg_rom_28_offset = 0x70000;
__prg_rom_29_offset = 0x74000;
__prg_rom_30_offset = 0x78000;
__prg_rom_fixed_offset = __prg_rom_size * 1024 - 0x4000;

MEMORY {
Expand All @@ -51,6 +81,21 @@ MEMORY {
prg_rom_12 : ORIGIN = __prg_rom_12_lma, LENGTH = __prg_rom_size >= 256 ? 0x4000 - 12 : 0
prg_rom_13 : ORIGIN = __prg_rom_13_lma, LENGTH = __prg_rom_size >= 256 ? 0x4000 - 12 : 0
prg_rom_14 : ORIGIN = __prg_rom_14_lma, LENGTH = __prg_rom_size >= 256 ? 0x4000 - 12 : 0
prg_rom_16 : ORIGIN = __prg_rom_16_lma, LENGTH = __prg_rom_size >= 512 ? 0x4000 - 12 : 0
prg_rom_17 : ORIGIN = __prg_rom_17_lma, LENGTH = __prg_rom_size >= 512 ? 0x4000 - 12 : 0
prg_rom_18 : ORIGIN = __prg_rom_18_lma, LENGTH = __prg_rom_size >= 512 ? 0x4000 - 12 : 0
prg_rom_19 : ORIGIN = __prg_rom_19_lma, LENGTH = __prg_rom_size >= 512 ? 0x4000 - 12 : 0
prg_rom_20 : ORIGIN = __prg_rom_20_lma, LENGTH = __prg_rom_size >= 512 ? 0x4000 - 12 : 0
prg_rom_21 : ORIGIN = __prg_rom_21_lma, LENGTH = __prg_rom_size >= 512 ? 0x4000 - 12 : 0
prg_rom_22 : ORIGIN = __prg_rom_22_lma, LENGTH = __prg_rom_size >= 512 ? 0x4000 - 12 : 0
prg_rom_23 : ORIGIN = __prg_rom_23_lma, LENGTH = __prg_rom_size >= 512 ? 0x4000 - 12 : 0
prg_rom_24 : ORIGIN = __prg_rom_24_lma, LENGTH = __prg_rom_size >= 512 ? 0x4000 - 12 : 0
prg_rom_25 : ORIGIN = __prg_rom_25_lma, LENGTH = __prg_rom_size >= 512 ? 0x4000 - 12 : 0
prg_rom_26 : ORIGIN = __prg_rom_26_lma, LENGTH = __prg_rom_size >= 512 ? 0x4000 - 12 : 0
prg_rom_27 : ORIGIN = __prg_rom_27_lma, LENGTH = __prg_rom_size >= 512 ? 0x4000 - 12 : 0
prg_rom_28 : ORIGIN = __prg_rom_28_lma, LENGTH = __prg_rom_size >= 512 ? 0x4000 - 12 : 0
prg_rom_29 : ORIGIN = __prg_rom_29_lma, LENGTH = __prg_rom_size >= 512 ? 0x4000 - 12 : 0
prg_rom_30 : ORIGIN = __prg_rom_30_lma, LENGTH = __prg_rom_size >= 512 ? 0x4000 - 12 : 0
prg_rom_fixed : ORIGIN = __prg_rom_fixed_lma, LENGTH = 0x4000 - 12

/* Reset stub. Arbitrarily put its VMA in the first bank. */
Expand Down Expand Up @@ -78,6 +123,21 @@ SECTIONS {
.prg_rom_12 : { *(.prg_rom_12 .prg_rom_12.*) } >prg_rom_12
.prg_rom_13 : { *(.prg_rom_13 .prg_rom_13.*) } >prg_rom_13
.prg_rom_14 : { *(.prg_rom_14 .prg_rom_14.*) } >prg_rom_14
.prg_rom_16 : { *(.prg_rom_16 .prg_rom_16.*) } >prg_rom_16
.prg_rom_17 : { *(.prg_rom_17 .prg_rom_17.*) } >prg_rom_17
.prg_rom_18 : { *(.prg_rom_18 .prg_rom_18.*) } >prg_rom_18
.prg_rom_19 : { *(.prg_rom_19 .prg_rom_19.*) } >prg_rom_19
.prg_rom_20 : { *(.prg_rom_20 .prg_rom_20.*) } >prg_rom_20
.prg_rom_21 : { *(.prg_rom_21 .prg_rom_21.*) } >prg_rom_21
.prg_rom_22 : { *(.prg_rom_22 .prg_rom_22.*) } >prg_rom_22
.prg_rom_23 : { *(.prg_rom_23 .prg_rom_23.*) } >prg_rom_23
.prg_rom_24 : { *(.prg_rom_24 .prg_rom_24.*) } >prg_rom_24
.prg_rom_25 : { *(.prg_rom_25 .prg_rom_25.*) } >prg_rom_25
.prg_rom_26 : { *(.prg_rom_26 .prg_rom_26.*) } >prg_rom_26
.prg_rom_27 : { *(.prg_rom_27 .prg_rom_27.*) } >prg_rom_27
.prg_rom_28 : { *(.prg_rom_28 .prg_rom_28.*) } >prg_rom_28
.prg_rom_29 : { *(.prg_rom_29 .prg_rom_29.*) } >prg_rom_29
.prg_rom_30 : { *(.prg_rom_30 .prg_rom_30.*) } >prg_rom_30
.prg_rom_fixed : { *(.prg_rom_fixed .prg_rom_fixed.*) } >prg_rom_fixed
}

Expand All @@ -90,6 +150,8 @@ SECTIONS {

PROVIDE(__prg_rom_size = 256);

__prg_rom_is_512 = __prg_rom_size >= 512 ? 1 : 0;

OUTPUT_FORMAT {
INCLUDE ines-header.ld
FULL(prg_rom_0) FULL(reset, 0, LENGTH(prg_rom_0) ? LENGTH(reset) : 0)
Expand All @@ -108,5 +170,25 @@ OUTPUT_FORMAT {
FULL(prg_rom_13) FULL(reset, 0, LENGTH(prg_rom_13) ? LENGTH(reset) : 0)
FULL(prg_rom_14) FULL(reset, 0, LENGTH(prg_rom_14) ? LENGTH(reset) : 0)
FULL(prg_rom_fixed) FULL(reset_fixed)

FULL(prg_rom_16) FULL(reset, 0, LENGTH(prg_rom_16) ? LENGTH(reset) : 0)
FULL(prg_rom_17) FULL(reset, 0, LENGTH(prg_rom_17) ? LENGTH(reset) : 0)
FULL(prg_rom_18) FULL(reset, 0, LENGTH(prg_rom_18) ? LENGTH(reset) : 0)
FULL(prg_rom_19) FULL(reset, 0, LENGTH(prg_rom_19) ? LENGTH(reset) : 0)
FULL(prg_rom_20) FULL(reset, 0, LENGTH(prg_rom_20) ? LENGTH(reset) : 0)
FULL(prg_rom_21) FULL(reset, 0, LENGTH(prg_rom_21) ? LENGTH(reset) : 0)
FULL(prg_rom_22) FULL(reset, 0, LENGTH(prg_rom_22) ? LENGTH(reset) : 0)
FULL(prg_rom_23) FULL(reset, 0, LENGTH(prg_rom_23) ? LENGTH(reset) : 0)
FULL(prg_rom_24) FULL(reset, 0, LENGTH(prg_rom_24) ? LENGTH(reset) : 0)
FULL(prg_rom_25) FULL(reset, 0, LENGTH(prg_rom_25) ? LENGTH(reset) : 0)
FULL(prg_rom_26) FULL(reset, 0, LENGTH(prg_rom_26) ? LENGTH(reset) : 0)
FULL(prg_rom_27) FULL(reset, 0, LENGTH(prg_rom_27) ? LENGTH(reset) : 0)
FULL(prg_rom_28) FULL(reset, 0, LENGTH(prg_rom_28) ? LENGTH(reset) : 0)
FULL(prg_rom_29) FULL(reset, 0, LENGTH(prg_rom_29) ? LENGTH(reset) : 0)
FULL(prg_rom_30) FULL(reset, 0, LENGTH(prg_rom_30) ? LENGTH(reset) : 0)

FULL(prg_rom_fixed, 0, __prg_rom_size >= 512 ? LENGTH(prg_rom_fixed) : 0)
FULL(reset_fixed, 0, __prg_rom_size >= 512 ? LENGTH(reset_fixed) : 0)

FULL(chr_rom)
}
1 change: 1 addition & 0 deletions test/nes-mmc1/CMakeLists.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@ add_nes_test(prg-rom-32)
add_nes_test(prg-rom-64)
add_nes_test(prg-rom-128)
add_nes_test(prg-rom-256)
add_nes_test(prg-rom-512)

add_nes_test(prg-ram)

Expand Down
77 changes: 77 additions & 0 deletions test/nes-mmc1/prg-rom-512.c
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Original file line number Diff line number Diff line change
@@ -0,0 +1,77 @@
#include <mapper.h>
#include <peekpoke.h>
#include <stdlib.h>

MAPPER_PRG_ROM_KB(512);

volatile const char c[15000] = {1, [14999] = 2};

__attribute__((section(".prg_rom_0.rodata"))) volatile const char d[15000] = {
3, [14999] = 4};

__attribute__((section(".prg_rom_14.rodata"))) volatile const char e[15000] = {
5, [14999] = 6};

__attribute__((section(".prg_rom_29.rodata"))) volatile const char f[15000] = {
7, [14999] = 8};


__attribute__((noinline, section(".prg_rom_0.text"))) char bank_0_fn(void) {
asm volatile("");
return 7;
}

__attribute__((noinline, section(".prg_rom_14.text"))) char bank_14_fn(void) {
asm volatile("");
return 8;
}

__attribute__((noinline, section(".prg_rom_29.text"))) char bank_29_fn(void) {
asm volatile("");
return 10;
}

int main(void) {
if ((unsigned)c < 0xc000)
return EXIT_FAILURE;
if ((unsigned)d >= 0xc000)
return EXIT_FAILURE;
if ((unsigned)e >= 0xc000)
return EXIT_FAILURE;
if ((unsigned)f >= 0xc000)
return EXIT_FAILURE;
if (c[0] != 1 || c[14999] != 2)
return EXIT_FAILURE;

set_prg_bank(0);
if (c[0] != 1 || c[14999] != 2)
return EXIT_FAILURE;
if (d[0] != 3 || d[14999] != 4)
return EXIT_FAILURE;

set_prg_bank(14);
if (c[0] != 1 || c[14999] != 2)
return EXIT_FAILURE;
if (e[0] != 5 || e[14999] != 6)
return EXIT_FAILURE;

set_prg_bank(29);
if (c[0] != 1 || c[14999] != 2)
return EXIT_FAILURE;
if (e[0] != 7 || e[14999] != 8)
return EXIT_FAILURE;

set_prg_bank(0);
if ((unsigned)bank_0_fn >= 0xc000 || bank_0_fn() != 7)
return EXIT_FAILURE;

set_prg_bank(14);
if ((unsigned)bank_14_fn >= 0xc000 || bank_14_fn() != 8)
return EXIT_FAILURE;

set_prg_bank(29);
if ((unsigned)bank_29_fn >= 0xc000 || bank_29_fn() != 10)
return EXIT_FAILURE;

return EXIT_SUCCESS;
}