Re: [Qemu-devel] [PATCH v6 08/11] target-avr: adding instruction translation

[Richard Henderson <rth@twiddle.net>]

On 06/12/2016 12:01 PM, Michael Rolnik wrote:
> +void gen_push_ret(CPUAVRState *env, int ret)
> +{
> +    if (avr_feature(env, AVR_FEATURE_1_BYTE_PC)) {
> +
> +        TCGv t0 = tcg_const_i32((ret & 0x0000ff));
> +
> +        tcg_gen_qemu_st8(t0, cpu_sp, MMU_DATA_IDX);
> +        tcg_gen_subi_tl(cpu_sp, cpu_sp, 1);
> +
> +        tcg_temp_free_i32(t0);
> +    } else if (avr_feature(env, AVR_FEATURE_2_BYTE_PC)) {
> +
> +        TCGv t0 = tcg_const_i32((ret & 0x00ffff));
> +
> +        tcg_gen_qemu_st16(t0, cpu_sp, MMU_DATA_IDX);
> +        tcg_gen_subi_tl(cpu_sp, cpu_sp, 2);

This stores to the wrong bytes.  You need

	tcg_gen_subi_tl(cpu_sp, cpu_sp, 1);
	tcg_gen_qemu_st_tl(t0, cpu_sp, MMU_DATA_IDX, MO_BEUW);
	tcg_gen_subi_tl(cpu_sp, cpu_sp, 1);

> +    } else if (avr_feature(env, AVR_FEATURE_3_BYTE_PC)) {
> +
> +        TCGv t0 = tcg_const_i32((ret & 0x0000ff));
> +        TCGv t1 = tcg_const_i32((ret & 0xffff00) >> 8);
> +
> +        tcg_gen_qemu_st8(t0, cpu_sp, MMU_DATA_IDX);
> +        tcg_gen_subi_tl(cpu_sp, cpu_sp, 1);
> +
> +        tcg_gen_qemu_st16(t1, cpu_sp, MMU_DATA_IDX);
> +        tcg_gen_subi_tl(cpu_sp, cpu_sp, 2);

Similarly.

> +void gen_pop_ret(CPUAVRState *env, TCGv ret)
> +{
> +    if (avr_feature(env, AVR_FEATURE_1_BYTE_PC)) {
> +
> +        tcg_gen_addi_tl(cpu_sp, cpu_sp, 1);
> +        tcg_gen_qemu_ld8u(ret, cpu_sp, MMU_DATA_IDX);
> +    } else if (avr_feature(env, AVR_FEATURE_2_BYTE_PC)) {
> +
> +        tcg_gen_addi_tl(cpu_sp, cpu_sp, 2);
> +        tcg_gen_qemu_ld16u(ret, cpu_sp, MMU_DATA_IDX);

Similarly,

	tcg_gen_addi_tl(cpu_sp, cpu_sp, 1);
	tcg_gen_qemu_ld_tl(ret, cpu_sp, MMU_DATA_IDX, MO_BEUW);
	tcg_gen_addi_tl(cpu_sp, cpu_sp, 1);


> +    } else if (avr_feature(env, AVR_FEATURE_3_BYTE_PC)) {
> +
> +        TCGv t0 = tcg_temp_new_i32();
> +
> +        tcg_gen_addi_tl(cpu_sp, cpu_sp, 1);
> +        tcg_gen_qemu_ld8u(ret, cpu_sp, MMU_DATA_IDX);
> +
> +        tcg_gen_addi_tl(cpu_sp, cpu_sp, 2);
> +        tcg_gen_qemu_ld16u(t0, cpu_sp, MMU_DATA_IDX);
> +
> +        tcg_gen_shli_tl(t0, t0, 16);
> +        tcg_gen_or_tl(ret, ret, t0);

You're putting t0 at the wrong end.

	tcg_gen_addi_tl(cpu_sp, cpu_sp, 1);
	tcg_gen_qemu_ld_tl(t0, cpu_sp, MMU_DATA_IDX, MO_UB);
	tcg_gen_addi_tl(cpu_sp, cpu_sp, 1);
	tcg_gen_qemu_ld_tl(ret, cpu_sp, MMU_DATA_IDX, MO_BEUW);	
	tcg_gen_addi_tl(cpu_sp, cpu_sp, 1);
	tcg_gen_deposit_tl(ret, ret, t0, 16, 8);



r~