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target/mips: Add a placeholder for R5900 SQ, handle user mode RDHWR 

Add placeholder for SQ instruction, handle RDHWR.

Reviewed-by: Aleksandar Markovic <amarkovic@wavecomp.com>
Signed-off-by: Fredrik Noring <noring@nocrew.org>
Signed-off-by: Aleksandar Markovic <amarkovic@wavecomp.com>
This commit is contained in:
Fredrik Noring 2018-10-21 17:35:41 +02:00 committed by Aleksandar Markovic
parent dd581bf97d
commit bb41e74b66
1 changed files with 52 additions and 1 deletions
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53
target/mips/translate.c
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@ -24420,6 +24420,53 @@ static void decode_opc_special3_legacy(CPUMIPSState *env, DisasContext *ctx)
}
}
static void gen_tx79_sq(DisasContext *ctx, int base, int rt, int offset)
{
generate_exception_end(ctx, EXCP_RI); /* TODO: TX79_SQ */
}
/*
* The TX79-specific instruction Store Quadword
*
* +--------+-------+-------+------------------------+
* | 011111 | base | rt | offset | SQ
* +--------+-------+-------+------------------------+
* 6 5 5 16
*
* has the same opcode as the Read Hardware Register instruction
*
* +--------+-------+-------+-------+-------+--------+
* | 011111 | 00000 | rt | rd | 00000 | 111011 | RDHWR
* +--------+-------+-------+-------+-------+--------+
* 6 5 5 5 5 6
*
* that is required, trapped and emulated by the Linux kernel. However, all
* RDHWR encodings yield address error exceptions on the TX79 since the SQ
* offset is odd. Therefore all valid SQ instructions can execute normally.
* In user mode, QEMU must verify the upper and lower 11 bits to distinguish
* between SQ and RDHWR, as the Linux kernel does.
*/
static void decode_tx79_sq(CPUMIPSState *env, DisasContext *ctx)
{
int base = extract32(ctx->opcode, 21, 5);
int rt = extract32(ctx->opcode, 16, 5);
int offset = extract32(ctx->opcode, 0, 16);
#ifdef CONFIG_USER_ONLY
uint32_t op1 = MASK_SPECIAL3(ctx->opcode);
uint32_t op2 = extract32(ctx->opcode, 6, 5);
if (base == 0 && op2 == 0 && op1 == OPC_RDHWR) {
int rd = extract32(ctx->opcode, 11, 5);
gen_rdhwr(ctx, rt, rd, 0);
return;
}
#endif
gen_tx79_sq(ctx, base, rt, offset);
}
static void decode_opc_special3(CPUMIPSState *env, DisasContext *ctx)
{
int rs, rt, rd, sa;
@ -25720,7 +25767,11 @@ static void decode_opc(CPUMIPSState *env, DisasContext *ctx)
decode_opc_special2_legacy(env, ctx);
break;
case OPC_SPECIAL3:
decode_opc_special3(env, ctx);
if (ctx->insn_flags & INSN_R5900) {
decode_tx79_sq(env, ctx); /* TX79_SQ */
} else {
decode_opc_special3(env, ctx);
}
break;
case OPC_REGIMM:
op1 = MASK_REGIMM(ctx->opcode);