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GBA: Resolve shifting negative value issue in some thumb/arm opcodes
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@rkitover
retro-wertz authored and rkitover committed Jan 17, 2019
1 parent 59f76d0 commit 093818a
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Showing 2 changed files with 31 additions and 148 deletions.
12 changes: 4 additions & 8 deletions src/gba/GBA-arm.cpp
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Expand Up @@ -2575,10 +2575,8 @@ static INSN_REGPARM void arm9F0(uint32_t opcode)
// B <offset>
static INSN_REGPARM void armA00(uint32_t opcode)
{
int offset = opcode & 0x00FFFFFF;
if (offset & 0x00800000)
offset |= 0xFF000000; // negative offset
reg[15].I += offset << 2;
int32_t offset = ((int32_t)(opcode & 0x00FFFFFF) << 8) >> 6;
reg[15].I += offset;
armNextPC = reg[15].I;
reg[15].I += 4;
ARM_PREFETCH;
Expand All @@ -2590,11 +2588,9 @@ static INSN_REGPARM void armA00(uint32_t opcode)
// BL <offset>
static INSN_REGPARM void armB00(uint32_t opcode)
{
int offset = opcode & 0x00FFFFFF;
if (offset & 0x00800000)
offset |= 0xFF000000; // negative offset
int32_t offset = ((int32_t)(opcode & 0x00FFFFFF) << 8) >> 6;
reg[14].I = reg[15].I - 4;
reg[15].I += offset << 2;
reg[15].I += offset;
armNextPC = reg[15].I;
reg[15].I += 4;
ARM_PREFETCH;
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167 changes: 27 additions & 140 deletions src/gba/GBA-thumb.cpp
View file
Expand Up @@ -1700,215 +1700,102 @@ static INSN_REGPARM void thumbC8(uint32_t opcode)
}
// Conditional branches ///////////////////////////////////////////////////
#define THUMB_CONDITIONAL_BRANCH(COND) \
UPDATE_OLDREG; \
clockTicks = codeTicksAccessSeq16(armNextPC) + 1; \
if (COND) { \
uint32_t offset = (uint32_t)((int8_t)(opcode & 0xFF)) << 1; \
reg[15].I += offset; \
armNextPC = reg[15].I; \
reg[15].I += 2; \
THUMB_PREFETCH; \
clockTicks += codeTicksAccessSeq16(armNextPC) \
+ codeTicksAccess16(armNextPC) + 2; \
busPrefetchCount = 0; \
}
// BEQ offset
static INSN_REGPARM void thumbD0(uint32_t opcode)
{
UPDATE_OLDREG;
clockTicks = codeTicksAccessSeq16(armNextPC) + 1;
if (Z_FLAG) {
reg[15].I += ((int8_t)(opcode & 0xFF)) << 1;
armNextPC = reg[15].I;
reg[15].I += 2;
THUMB_PREFETCH;
clockTicks += codeTicksAccessSeq16(armNextPC) + codeTicksAccess16(armNextPC) + 2;
busPrefetchCount = 0;
}
THUMB_CONDITIONAL_BRANCH(Z_FLAG);
}
// BNE offset
static INSN_REGPARM void thumbD1(uint32_t opcode)
{
UPDATE_OLDREG;
clockTicks = codeTicksAccessSeq16(armNextPC) + 1;
if (!Z_FLAG) {
reg[15].I += ((int8_t)(opcode & 0xFF)) << 1;
armNextPC = reg[15].I;
reg[15].I += 2;
THUMB_PREFETCH;
clockTicks += codeTicksAccessSeq16(armNextPC) + codeTicksAccess16(armNextPC) + 2;
busPrefetchCount = 0;
}
THUMB_CONDITIONAL_BRANCH(!Z_FLAG);
}
// BCS offset
static INSN_REGPARM void thumbD2(uint32_t opcode)
{
UPDATE_OLDREG;
clockTicks = codeTicksAccessSeq16(armNextPC) + 1;
if (C_FLAG) {
reg[15].I += ((int8_t)(opcode & 0xFF)) << 1;
armNextPC = reg[15].I;
reg[15].I += 2;
THUMB_PREFETCH;
clockTicks += codeTicksAccessSeq16(armNextPC) + codeTicksAccess16(armNextPC) + 2;
busPrefetchCount = 0;
}
THUMB_CONDITIONAL_BRANCH(C_FLAG);
}
// BCC offset
static INSN_REGPARM void thumbD3(uint32_t opcode)
{
UPDATE_OLDREG;
clockTicks = codeTicksAccessSeq16(armNextPC) + 1;
if (!C_FLAG) {
reg[15].I += ((int8_t)(opcode & 0xFF)) << 1;
armNextPC = reg[15].I;
reg[15].I += 2;
THUMB_PREFETCH;
clockTicks += codeTicksAccessSeq16(armNextPC) + codeTicksAccess16(armNextPC) + 2;
busPrefetchCount = 0;
}
THUMB_CONDITIONAL_BRANCH(!C_FLAG);
}
// BMI offset
static INSN_REGPARM void thumbD4(uint32_t opcode)
{
UPDATE_OLDREG;
clockTicks = codeTicksAccessSeq16(armNextPC) + 1;
if (N_FLAG) {
reg[15].I += ((int8_t)(opcode & 0xFF)) << 1;
armNextPC = reg[15].I;
reg[15].I += 2;
THUMB_PREFETCH;
clockTicks += codeTicksAccessSeq16(armNextPC) + codeTicksAccess16(armNextPC) + 2;
busPrefetchCount = 0;
}
THUMB_CONDITIONAL_BRANCH(N_FLAG);
}
// BPL offset
static INSN_REGPARM void thumbD5(uint32_t opcode)
{
UPDATE_OLDREG;
clockTicks = codeTicksAccessSeq16(armNextPC) + 1;
if (!N_FLAG) {
reg[15].I += ((int8_t)(opcode & 0xFF)) << 1;
armNextPC = reg[15].I;
reg[15].I += 2;
THUMB_PREFETCH;
clockTicks += codeTicksAccessSeq16(armNextPC) + codeTicksAccess16(armNextPC) + 2;
busPrefetchCount = 0;
}
THUMB_CONDITIONAL_BRANCH(!N_FLAG);
}
// BVS offset
static INSN_REGPARM void thumbD6(uint32_t opcode)
{
UPDATE_OLDREG;
clockTicks = codeTicksAccessSeq16(armNextPC) + 1;
if (V_FLAG) {
reg[15].I += ((int8_t)(opcode & 0xFF)) << 1;
armNextPC = reg[15].I;
reg[15].I += 2;
THUMB_PREFETCH;
clockTicks += codeTicksAccessSeq16(armNextPC) + codeTicksAccess16(armNextPC) + 2;
busPrefetchCount = 0;
}
THUMB_CONDITIONAL_BRANCH(V_FLAG);
}
// BVC offset
static INSN_REGPARM void thumbD7(uint32_t opcode)
{
UPDATE_OLDREG;
clockTicks = codeTicksAccessSeq16(armNextPC) + 1;
if (!V_FLAG) {
reg[15].I += ((int8_t)(opcode & 0xFF)) << 1;
armNextPC = reg[15].I;
reg[15].I += 2;
THUMB_PREFETCH;
clockTicks += codeTicksAccessSeq16(armNextPC) + codeTicksAccess16(armNextPC) + 2;
busPrefetchCount = 0;
}
THUMB_CONDITIONAL_BRANCH(!V_FLAG);
}
// BHI offset
static INSN_REGPARM void thumbD8(uint32_t opcode)
{
UPDATE_OLDREG;
clockTicks = codeTicksAccessSeq16(armNextPC) + 1;
if (C_FLAG && !Z_FLAG) {
reg[15].I += ((int8_t)(opcode & 0xFF)) << 1;
armNextPC = reg[15].I;
reg[15].I += 2;
THUMB_PREFETCH;
clockTicks += codeTicksAccessSeq16(armNextPC) + codeTicksAccess16(armNextPC) + 2;
busPrefetchCount = 0;
}
THUMB_CONDITIONAL_BRANCH(C_FLAG && !Z_FLAG);
}
// BLS offset
static INSN_REGPARM void thumbD9(uint32_t opcode)
{
UPDATE_OLDREG;
clockTicks = codeTicksAccessSeq16(armNextPC) + 1;
if (!C_FLAG || Z_FLAG) {
reg[15].I += ((int8_t)(opcode & 0xFF)) << 1;
armNextPC = reg[15].I;
reg[15].I += 2;
THUMB_PREFETCH;
clockTicks += codeTicksAccessSeq16(armNextPC) + codeTicksAccess16(armNextPC) + 2;
busPrefetchCount = 0;
}
THUMB_CONDITIONAL_BRANCH(!C_FLAG || Z_FLAG);
}
// BGE offset
static INSN_REGPARM void thumbDA(uint32_t opcode)
{
UPDATE_OLDREG;
clockTicks = codeTicksAccessSeq16(armNextPC) + 1;
if (N_FLAG == V_FLAG) {
reg[15].I += ((int8_t)(opcode & 0xFF)) << 1;
armNextPC = reg[15].I;
reg[15].I += 2;
THUMB_PREFETCH;
clockTicks += codeTicksAccessSeq16(armNextPC) + codeTicksAccess16(armNextPC) + 2;
busPrefetchCount = 0;
}
THUMB_CONDITIONAL_BRANCH(N_FLAG == V_FLAG);
}
// BLT offset
static INSN_REGPARM void thumbDB(uint32_t opcode)
{
UPDATE_OLDREG;
clockTicks = codeTicksAccessSeq16(armNextPC) + 1;
if (N_FLAG != V_FLAG) {
reg[15].I += ((int8_t)(opcode & 0xFF)) << 1;
armNextPC = reg[15].I;
reg[15].I += 2;
THUMB_PREFETCH;
clockTicks += codeTicksAccessSeq16(armNextPC) + codeTicksAccess16(armNextPC) + 2;
busPrefetchCount = 0;
}
THUMB_CONDITIONAL_BRANCH(N_FLAG != V_FLAG);
}
// BGT offset
static INSN_REGPARM void thumbDC(uint32_t opcode)
{
UPDATE_OLDREG;
clockTicks = codeTicksAccessSeq16(armNextPC) + 1;
if (!Z_FLAG && (N_FLAG == V_FLAG)) {
reg[15].I += ((int8_t)(opcode & 0xFF)) << 1;
armNextPC = reg[15].I;
reg[15].I += 2;
THUMB_PREFETCH;
clockTicks += codeTicksAccessSeq16(armNextPC) + codeTicksAccess16(armNextPC) + 2;
busPrefetchCount = 0;
}
THUMB_CONDITIONAL_BRANCH(!Z_FLAG && (N_FLAG == V_FLAG));
}
// BLE offset
static INSN_REGPARM void thumbDD(uint32_t opcode)
{
UPDATE_OLDREG;
clockTicks = codeTicksAccessSeq16(armNextPC);
if (Z_FLAG || (N_FLAG != V_FLAG)) {
reg[15].I += ((int8_t)(opcode & 0xFF)) << 1;
armNextPC = reg[15].I;
reg[15].I += 2;
THUMB_PREFETCH;
clockTicks += codeTicksAccessSeq16(armNextPC) + codeTicksAccess16(armNextPC) + 2;
busPrefetchCount = 0;
}
THUMB_CONDITIONAL_BRANCH(Z_FLAG || (N_FLAG != V_FLAG));
}
// SWI, B, BL /////////////////////////////////////////////////////////////
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