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target/mips: Support R5900 three-operand MULT and MULTU instructions

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The three-operand MULT and MULTU are the only R5900-specific
instructions emitted by GCC 7.3. The R5900 also implements the three-
operand MADD and MADDU instructions, but they are omitted in QEMU for
now since they are absent in programs compiled by current GCC versions.

Likewise, the R5900-specific pipeline 1 instruction variants MULT1,
MULTU1, DIV1, DIVU1, MADD1, MADDU1, MFHI1, MFLO1, MTHI1 and MTLO1
are omitted here as well.

Backports commit 21e8e8b230af38b6bd8c953fa5f31e4a5a128e1c from qemu
This commit is contained in:
Fredrik Noring 2018-11-10 11:57:42 -05:00 committed by Lioncash
parent 7da9860cf5
commit 91cd7c20e5
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GPG key ID: 4E3C3CC1031BA9C7
1 changed files with 75 additions and 0 deletions
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75
qemu/target/mips/translate.c
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@ -4826,6 +4826,79 @@ static void gen_muldiv(DisasContext *ctx, uint32_t opc,
tcg_temp_free(tcg_ctx, t1);
}
/*
* These MULT and MULTU instructions implemented in for example the
* Toshiba/Sony R5900 and the Toshiba TX19, TX39 and TX79 core
* architectures are special three-operand variants with the syntax
*
* MULT[U] rd, rs, rt
*
* such that
*
* (rd, LO, HI) <- rs * rt
*
* where the low-order 32-bits of the result is placed into both the
* GPR rd and the special register LO. The high-order 32-bits of the
* result is placed into the special register HI.
*
* If the GPR rd is omitted in assembly language, it is taken to be 0,
* which is the zero register that always reads as 0.
*/
static void gen_mul_txx9(DisasContext *ctx, uint32_t opc,
int rd, int rs, int rt)
{
TCGContext *tcg_ctx = ctx->uc->tcg_ctx;
TCGv t0 = tcg_temp_new(tcg_ctx);
TCGv t1 = tcg_temp_new(tcg_ctx);
int acc = 0;
gen_load_gpr(ctx, t0, rs);
gen_load_gpr(ctx, t1, rt);
switch (opc) {
case OPC_MULT:
{
TCGv_i32 t2 = tcg_temp_new_i32(tcg_ctx);
TCGv_i32 t3 = tcg_temp_new_i32(tcg_ctx);
tcg_gen_trunc_tl_i32(tcg_ctx, t2, t0);
tcg_gen_trunc_tl_i32(tcg_ctx, t3, t1);
tcg_gen_muls2_i32(tcg_ctx, t2, t3, t2, t3);
if (rd) {
tcg_gen_ext_i32_tl(tcg_ctx, tcg_ctx->cpu_gpr[rd], t2);
}
tcg_gen_ext_i32_tl(tcg_ctx, tcg_ctx->cpu_LO[acc], t2);
tcg_gen_ext_i32_tl(tcg_ctx, tcg_ctx->cpu_HI[acc], t3);
tcg_temp_free_i32(tcg_ctx, t2);
tcg_temp_free_i32(tcg_ctx, t3);
}
break;
case OPC_MULTU:
{
TCGv_i32 t2 = tcg_temp_new_i32(tcg_ctx);
TCGv_i32 t3 = tcg_temp_new_i32(tcg_ctx);
tcg_gen_trunc_tl_i32(tcg_ctx, t2, t0);
tcg_gen_trunc_tl_i32(tcg_ctx, t3, t1);
tcg_gen_mulu2_i32(tcg_ctx, t2, t3, t2, t3);
if (rd) {
tcg_gen_ext_i32_tl(tcg_ctx, tcg_ctx->cpu_gpr[rd], t2);
}
tcg_gen_ext_i32_tl(tcg_ctx, tcg_ctx->cpu_LO[acc], t2);
tcg_gen_ext_i32_tl(tcg_ctx, tcg_ctx->cpu_HI[acc], t3);
tcg_temp_free_i32(tcg_ctx, t2);
tcg_temp_free_i32(tcg_ctx, t3);
}
break;
default:
MIPS_INVAL("mul TXx9");
generate_exception_end(ctx, EXCP_RI);
goto out;
}
out:
tcg_temp_free(tcg_ctx, t0);
tcg_temp_free(tcg_ctx, t1);
}
static void gen_mul_vr54xx (DisasContext *ctx, uint32_t opc,
int rd, int rs, int rt)
{
@ -23641,6 +23714,8 @@ static void decode_opc_special_legacy(CPUMIPSState *env, DisasContext *ctx)
check_insn(ctx, INSN_VR54XX);
op1 = MASK_MUL_VR54XX(ctx->opcode);
gen_mul_vr54xx(ctx, op1, rd, rs, rt);
} else if (ctx->insn_flags & INSN_R5900) {
gen_mul_txx9(ctx, op1, rd, rs, rt);
} else {
gen_muldiv(ctx, op1, rd & 3, rs, rt);
}