Reimplement arm load stubs and fix BIOS handler
This fixes unallowed BIOS accesses (outside from BIOS) which fixes some games like Silent Scope but also Zelda (fixes rolling as reported by neonloop!)
This commit is contained in:
David Guillen Fandos
parent
221b8ff115
commit
ac3e75a107
142
arm/arm_stub.S
142
arm/arm_stub.S
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@ -747,72 +747,124 @@ lookup_pc_arm:
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bx r0 @ jump to new ARM block
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#define sign_extend_u8(reg)
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#define sign_extend_u16(reg)
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#define sign_extend_u32(reg)
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#define exec_ld_op_s8(mirrorbits) ;\
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mov r0, r0, lsl #(32 - mirrorbits) ;\
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mov r0, r0, lsr #(32 - mirrorbits) ;\
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ldrsb r0, [r2, r0]
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#define sign_extend_s8(reg) ;\
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sxtb reg, reg
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#define exec_ld_op_u8(mirrorbits) ;\
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mov r0, r0, lsl #(32 - mirrorbits) ;\
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mov r0, r0, lsr #(32 - mirrorbits) ;\
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ldrb r0, [r2, r0]
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#define sign_extend_s16(reg) ;\
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sxth reg, reg
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#define exec_ld_op_s16(mirrorbits) ;\
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mov r0, r0, lsl #(32 - mirrorbits) ;\
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mov r0, r0, lsr #(32 - mirrorbits) ;\
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ldrsh r0, [r2, r0]
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#define execute_load_op_u8(load_op) ;\
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mov r0, r0, lsl #17 ;\
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load_op r0, [r2, r0, lsr #17] ;\
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#define exec_ld_op_u16(mirrorbits) ;\
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mov r0, r0, lsl #(32 - mirrorbits) ;\
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mov r0, r0, lsr #(32 - mirrorbits) ;\
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ldrh r0, [r2, r0]
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#define execute_load_op_s8(load_op) ;\
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mov r0, r0, lsl #17 ;\
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mov r0, r0, lsr #17 ;\
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load_op r0, [r2, r0] ;\
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#define execute_load_op_u16(load_op) ;\
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execute_load_op_s8(load_op) ;\
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#define execute_load_op_s16(load_op) ;\
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execute_load_op_s8(load_op) ;\
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#define execute_load_op_u16(load_op) ;\
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execute_load_op_s8(load_op) ;\
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#define execute_load_op_u32(load_op) ;\
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execute_load_op_u8(load_op) ;\
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#define exec_ld_op_u32(mirrorbits) ;\
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mov r0, r0, lsl #(32 - mirrorbits) ;\
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ldr r0, [r2, r0, lsr #(32 - mirrorbits)] ;\
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#define execute_load_builder(load_type, load_function, load_op, mask) ;\
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#define execute_load_builder(load_type, albits, load_function) ;\
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;\
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defsymbl(execute_load_##load_type) ;\
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save_flags() ;\
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tst r0, mask /* make sure address is in range */;\
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bne ext_load_##load_type /* if not do ext load */;\
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.if albits >= 1 ;\
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ror r1, r0, #(albits) /* move alignment bits to MSB */;\
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usat r1, #4, r1, asr #(24-albits) /* r1 contains [0-15] */;\
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.else ;\
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usat r1, #4, r0, asr #24 /* r1 contains [0-15] */;\
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.endif ;\
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ldr pc, [pc, r1, lsl #2] /* use jump table below */;\
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nop ;\
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;\
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.long ld_bios_##load_type /* 0 BIOS */;\
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.long ld_slow_##load_type /* 1 Bad region */;\
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.long ld_ewram_##load_type /* 2 EWRAM */;\
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.long ld_iwram_##load_type /* 3 IWRAM */;\
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.long ld_ioram_##load_type /* 4 I/O */;\
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.long ld_palram_##load_type /* 5 Palette RAM, via map */;\
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.long ld_rdmap_##load_type /* 6 VRAM area */;\
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.long ld_oamram_##load_type /* 7 OAM RAM */;\
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.long ld_rdmap_##load_type /* 8 ROM, via map */;\
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.long ld_rdmap_##load_type /* 9 ROM, via map */;\
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.long ld_rdmap_##load_type /* A ROM, via map */;\
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.long ld_rdmap_##load_type /* B ROM, via map */;\
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.long ld_rdmap_##load_type /* C ROM, via map */;\
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.long ld_slow_##load_type /* D ROM or EEPROM/FLASH */;\
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.long ld_slow_##load_type /* E EEPROM/FLASH */;\
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.long ld_slow_##load_type /* F Bad region */;\
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;\
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ld_bios_##load_type: /* BIOS area, need to verify PC */;\
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save_flags() ;\
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ldr r1, [lr] /* r1 = PC */;\
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mov r2, r1, lsr #15 /* r2 = High addr bits from PC */;\
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cmp r2, #0 ;\
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bne 10f /* Jump to slow handler */;\
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ldr r2, =bios_rom ;\
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exec_ld_op_##load_type(15) /* Clear upper bits (15 LSB) */;\
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restore_flags() ;\
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add pc, lr, #4 ;\
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;\
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ld_ewram_##load_type: /* EWRAM area */;\
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ldr r2, =(ewram) ;\
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exec_ld_op_##load_type(18) /* Clear upper bits (18 LSB) */;\
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add pc, lr, #4 ;\
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;\
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ld_iwram_##load_type: /* IWRAM area */;\
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ldr r2, =(iwram+0x8000) ;\
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exec_ld_op_##load_type(15) /* Clear upper bits (15 LSB) */;\
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add pc, lr, #4 ;\
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;\
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ld_ioram_##load_type: /* I/O RAM area */;\
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ldr r2, =io_registers ;\
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exec_ld_op_##load_type(10) /* Clear upper bits (10 LSB) */;\
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add pc, lr, #4 ;\
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;\
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ld_palram_##load_type: /* Palette RAM area */;\
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ldr r2, =palette_ram ;\
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exec_ld_op_##load_type(10) /* Clear upper bits (10 LSB) */;\
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add pc, lr, #4 ;\
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;\
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ld_oamram_##load_type: /* OAM RAM area */;\
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ldr r2, =oam_ram ;\
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exec_ld_op_##load_type(10) /* Clear upper bits (10 LSB) */;\
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add pc, lr, #4 ;\
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;\
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/* ROM area (or VRAM): uses generic memory handlers */ ;\
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ld_rdmap_##load_type: ;\
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ldr r2, =memory_map_read /* r2 = memory_map_read */;\
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mov r1, r0, lsr #15 /* r1 = page index of address */;\
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ldr r2, [r2, r1, lsl #2] /* r2 = memory page */;\
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ldr r2, [r2, r1, lsl #2] /* r2 = base addr */;\
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;\
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cmp r2, #0 /* see if map is ext */;\
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beq ext_load_##load_type /* if so do ext load */;\
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exec_ld_op_##load_type(15) /* Pages are 32KB big */;\
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add pc, lr, #4 ;\
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;\
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execute_load_op_##load_type(load_op) ;\
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restore_flags() ;\
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add pc, lr, #4 /* return */;\
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;\
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ext_load_##load_type: ;\
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/* Slow load path, for open/unmapped loads */;\
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ld_slow_##load_type: ;\
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save_flags() ;\
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ldr r1, [lr] /* r1 = PC */;\
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10: ;\
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str r1, [reg_base, #REG_PC] /* update PC */;\
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call_c_function(read_memory##load_function) ;\
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sign_extend_##load_type(r0) /* sign extend result */;\
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call_c_function(load_function) ;\
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restore_flags() ;\
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add pc, lr, #4 /* return */;\
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;\
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.size execute_load_##load_type, .-execute_load_##load_type
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.pool
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execute_load_builder(u8, 8, ldrb, #0xF0000000)
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execute_load_builder(s8, 8, ldrsb, #0xF0000000)
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execute_load_builder(u16, 16, ldrh, #0xF0000001)
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execute_load_builder(s16, 16_signed, ldrsh, #0xF0000001)
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execute_load_builder(u32, 32, ldr, #0xF0000003)
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execute_load_builder(u8, 0, read_memory8)
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execute_load_builder(s8, 0, read_memory8s)
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execute_load_builder(u16, 1, read_memory16)
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execute_load_builder(s16, 1, read_memory16s)
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execute_load_builder(u32, 2, read_memory32)
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.data
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