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swizzle address with pre-swapped data instead of endian-swap

This commit is contained in:
lif 2023-12-25 00:01:56 -08:00
parent b1cf0addb1
commit 35711d50e0
4 changed files with 27 additions and 9 deletions
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BIN
bios/open_gba_bios.bigendian Normal file
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2
bios_data.S
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@ -5,5 +5,5 @@
.data
_open_gba_bios_rom:
open_gba_bios_rom:
.incbin "bios/open_gba_bios.bin"
.incbin "bios/open_gba_bios.bigendian"

14
common.h
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@ -137,15 +137,21 @@ typedef u32 fixed8_24;
#define eswap8(value) (value)
#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
#define eswap16(value) __builtin_bswap16(value)
#define eswap32(value) __builtin_bswap32(value)
// #define eswap16(value) __builtin_bswap16(value)
// #define eswap32(value) __builtin_bswap32(value)
#define eswap16(value) (value)
#define eswap32(value) (value)
#define swizzle_h(ofs) ((ofs) ^ 2)
#define swizzle_b(ofs) ((ofs) ^ 3)
#else
#define eswap16(value) (value)
#define eswap32(value) (value)
#define swizzle_h(ofs) (ofs)
#define swizzle_b(ofs) (ofs)
#endif
#define readaddress8(base, offset) eswap8( address8( base, offset))
#define readaddress16(base, offset) eswap16(address16(base, offset))
#define readaddress8(base, offset) eswap8(address8( base, swizzle_b(offset)))
#define readaddress16(base, offset) eswap16(address16(base, swizzle_h(offset)))
#define readaddress32(base, offset) eswap32(address32(base, offset))
#define read_ioreg(regnum) (eswap16(io_registers[(regnum)]))

20
mips/mips_emit.h
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@ -2027,6 +2027,9 @@ u32 execute_store_cpsr_body(u32 _cpsr, u32 address)
#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
#define emit_swizzle_h(r) mips_emit_xori(r, r, 2)
#define emit_swizzle_b(r) mips_emit_xori(r, r, 3)
/*
400230: 00042e00 sll a1,a0,0x18
400234: 00041602 srl v0,a0,0x18
@ -2076,6 +2079,9 @@ u32 execute_store_cpsr_body(u32 _cpsr, u32 address)
#else
#define emit_swizzle_h()
#define emit_swizzle_b()
#define emit_eswap32(r)
#define emit_eswap16(r, sext)
@ -2115,22 +2121,24 @@ static void emit_mem_access_loadop(
switch (size) {
case 2:
mips_emit_lw(reg_rv, reg_rv, (base_addr & 0xffff));
emit_eswap32(reg_rv);
break;
case 1:
if (signext) {
if (alignment) {
// Unaligned signed 16b load, is just a load byte (due to sign extension)
emit_swizzle_b(reg_rv);
mips_emit_lb(reg_rv, reg_rv, ((base_addr | 1) & 0xffff));
} else {
emit_swizzle_h(reg_rv);
mips_emit_lh(reg_rv, reg_rv, (base_addr & 0xffff));
}
} else {
emit_swizzle_h(reg_rv);
mips_emit_lhu(reg_rv, reg_rv, (base_addr & 0xffff));
}
emit_eswap16(reg_rv, signext);
break;
default:
emit_swizzle_b(reg_rv);
if (signext) {
mips_emit_lb(reg_rv, reg_rv, (base_addr & 0xffff));
} else {
@ -2392,8 +2400,10 @@ static void emit_pmemst_stub(
if (realsize == 2) {
mips_emit_lw(reg_temp, reg_temp, base_addr);
} else if (realsize == 1) {
emit_swizzle_h(reg_temp);
mips_emit_lh(reg_temp, reg_temp, base_addr);
} else {
emit_swizzle_b(reg_temp);
mips_emit_lb(reg_temp, reg_temp, base_addr);
}
// If the data is non zero, we just wrote over code
@ -2403,12 +2413,12 @@ static void emit_pmemst_stub(
// Store the data (delay slot from the SMC branch)
if (realsize == 2) {
emit_eswap32(reg_a1);
mips_emit_sw(reg_a1, reg_rv, base_addr);
} else if (realsize == 1) {
emit_eswap16(reg_a1, false);
emit_swizzle_h(reg_rv);
mips_emit_sh(reg_a1, reg_rv, base_addr);
} else {
emit_swizzle_b(reg_rv);
mips_emit_sb(reg_a1, reg_rv, base_addr);
}
@ -2488,7 +2498,9 @@ static void emit_palette_hdl(
if (realsize == 2) {
mips_emit_sw(reg_a1, reg_rv, 0x100);
} else if (realsize == 1) {
emit_swizzle_h(reg_rv);
mips_emit_sh(reg_a1, reg_rv, 0x100);
emit_swizzle_h(reg_rv); // TODO: ???
}
// Convert and store in mirror memory