Re: [PATCH-for-8.0 4/7] hw/mips/bootloader: Implement nanoMIPS LUI opcode

[Philippe Mathieu-Daudé]

On 10/12/22 16:54, Philippe Mathieu-Daudé wrote:
> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> ---
>   hw/mips/bootloader.c | 29 ++++++++++++++++++++++++++---
>   1 file changed, 26 insertions(+), 3 deletions(-)
>
> diff --git a/hw/mips/bootloader.c b/hw/mips/bootloader.c
> index 7f7d938f2e..997e74ee52 100644
> --- a/hw/mips/bootloader.c
> +++ b/hw/mips/bootloader.c
> @@ -120,11 +120,34 @@ static void bl_gen_jalr(void **p, bl_reg rs)
>       bl_gen_r_type(p, 0, rs, 0, BL_REG_RA, 0, 0x09);
>   }
>   
> +static void bl_gen_lui_nm(void **ptr, bl_reg rt, uint32_t imm20)
> +{
> +    uint16_t *p = (uint16_t *)*ptr;
> +    uint32_t insn = 0;

Hmm we should check if imm20 fits in 20-bit.

> +    insn = deposit32(insn, 26, 6, 0b111000);
> +    insn = deposit32(insn, 21, 5, rt);
> +    insn = deposit32(insn, 12, 9, extract32(imm20, 12, 9));
> +    insn = deposit32(insn, 2, 10, extract32(imm20, 21, 10));
> +    insn = deposit32(insn, 0, 1, sextract32(imm20, 31, 1));
> +
> +    stw_p(p, insn >> 16);
> +    p++;
> +    stw_p(p, insn >> 0);
> +    p++;
> +
> +    *ptr = p;
> +}