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dis/sim: fix handling of opcodes with two indexed operands. 

If the source operand is indexed, and the destination is symbolic (PC +
index), then the base for the destination index is the program counter
*after* having fetched the source index.

Also, the addition of the index is done modulo 2^16 if the base points
within the lower 64 kB of memory.
This commit is contained in:
Daniel Beer 2013-02-11 10:58:31 +13:00
parent 72e781d0eb
commit e9b6a77414
2 changed files with 38 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/sim.c
View File

@ -100,10 +100,10 @@ static int fetch_operand(struct sim_device *dev,
}
addr = MEM_GETW(dev, dev->regs[MSP430_REG_PC]);
dev->regs[MSP430_REG_PC] += 2;
if (reg != MSP430_REG_SR)
addr += dev->regs[reg];
dev->regs[MSP430_REG_PC] += 2;
break;
case MSP430_AMODE_INDIRECT:

58
util/dis.c
View File

@ -32,6 +32,14 @@
/* Disassembler
*/
static address_t add_index(address_t reg_base, uint16_t index)
{
if (reg_base >> 16)
return reg_base + index;
return (reg_base + index) & 0xffff;
}
static int decode_00xx(const uint8_t *code, address_t len,
struct msp430_instruction *insn)
{
@ -286,7 +294,8 @@ static int decode_single(const uint8_t *code, address_t offset,
if (size < 4)
return -1;
insn->dst_addr += (code[3] << 8) | code[2];
insn->dst_addr = add_index(insn->dst_addr,
(code[3] << 8) | code[2]);
return 4;
}
@ -306,6 +315,7 @@ static int decode_double(const uint8_t *code, address_t offset,
int need_dst = 0;
int ret = 2;
/* Decode and consume opcode */
insn->itype = MSP430_ITYPE_DOUBLE;
insn->op = op & 0xf000;
insn->dsize = (op & 0x0040) ? MSP430_DSIZE_BYTE : MSP430_DSIZE_WORD;
@ -316,21 +326,11 @@ static int decode_double(const uint8_t *code, address_t offset,
insn->dst_mode = (op >> 7) & 0x1;
insn->dst_reg = op & 0xf;
switch (insn->dst_mode) {
case MSP430_AMODE_REGISTER: break;
case MSP430_AMODE_INDEXED:
need_dst = 1;
if (insn->dst_reg == MSP430_REG_PC) {
insn->dst_mode = MSP430_AMODE_SYMBOLIC;
insn->dst_addr = offset + 2;
} else if (insn->dst_reg == MSP430_REG_SR)
insn->dst_mode = MSP430_AMODE_ABSOLUTE;
break;
default: break;
}
offset += 2;
code += 2;
size -= 2;
/* Decode and consume source operand */
switch (insn->src_mode) {
case MSP430_AMODE_REGISTER: break;
case MSP430_AMODE_INDEXED:
@ -338,7 +338,7 @@ static int decode_double(const uint8_t *code, address_t offset,
if (insn->src_reg == MSP430_REG_PC) {
insn->src_mode = MSP430_AMODE_SYMBOLIC;
insn->dst_addr = offset + 2;
insn->dst_addr = offset;
} else if (insn->src_reg == MSP430_REG_SR)
insn->src_mode = MSP430_AMODE_ABSOLUTE;
else if (insn->src_reg == MSP430_REG_R3)
@ -357,26 +357,40 @@ static int decode_double(const uint8_t *code, address_t offset,
default: break;
}
offset += 2;
code += 2;
size -= 2;
if (need_src) {
if (size < 2)
return -1;
insn->src_addr += (code[1] << 8) | code[0];
insn->src_addr = add_index(insn->src_addr,
((code[1] << 8) | code[0]));
offset += 2;
code += 2;
size -= 2;
ret += 2;
}
/* Decode and consume destination operand */
switch (insn->dst_mode) {
case MSP430_AMODE_REGISTER: break;
case MSP430_AMODE_INDEXED:
need_dst = 1;
if (insn->dst_reg == MSP430_REG_PC) {
insn->dst_mode = MSP430_AMODE_SYMBOLIC;
insn->dst_addr = offset;
} else if (insn->dst_reg == MSP430_REG_SR)
insn->dst_mode = MSP430_AMODE_ABSOLUTE;
break;
default: break;
}
if (need_dst) {
if (size < 2)
return -1;
insn->dst_addr += (code[1] << 8) | code[0];
insn->dst_addr = add_index(insn->dst_addr,
(code[1] << 8) | code[0]);
ret += 2;
}