Ghidra: "Complex" statements in action sections

[loudinthecloud]

I'm trying to write a constructor for the movi20s instruction of the SH-2A core. It is defined as follows:

MOVI20S (long i, long n)
/* MOVI20S #imm, Rn */
{
if (i&0x00080000) ==0) R[n]= (0x000FFFFF & (long) i);
else R[n]=(0xFFF00000 | (long) i);
R[n]<<=8;
PC+=4;
}

So I'd basically like to write something like this:

# MOVI20S #imm20, Rn
# 0000nnnniiii0001 iiiiiiiiiiiiiiii
# imm<<8 → sign extension → Rn
imm20s: "#"imm20Shifted is l_imm20_20_23 & l_imm20_00_16
    [ imm20Shifted = sext(((l_imm20_20_23 << 16) | l_imm20_00_16) << 8); ]
    { export *[ram]:4 imm20Shifted; }

:movi20s imm20s, l_rn_24_27       
    is l_opcode_28_31=0b0000 & l_rn_24_27 & l_opcode_16_19=0b0001 & imm20s
{
    l_rn_24_27 = imm20s;
}

But using sext in the action section will not compile... any idea how to use a "complex statement" both in the display section and the semantic section?

Thanks in advance.

[mumbel]

Just make another token similar to l_imm20_20_23 but signed

[loudinthecloud]

Just make another token similar to l_imm20_20_23 but signed

Thanks for the quick reply, I am making l_imm20_20_23 signed and it still doesn't work ->

define token instr32(32)
    l_disp_00_11 =      (0, 11)
    l_opcode_12_15 =    (12, 15)
    l_opcode_16_19 =    (16, 19)
    l_rm_20_23 =        (20, 23)
    l_rn_24_27 =        (24, 27)
    l_opcode_28_31 =    (28, 31)
    l_simm20_00_16 =    (0, 16) signed
    l_simm20_20_23 =    (20, 23) signed
;
...
imm20: "#"value is l_simm20_20_23 & l_simm20_00_16
    [ value = sext((l_simm20_20_23 << 16) | l_simm20_00_16); ]
    { export *[ram]:4 value; }

imm20s: "#"value is l_simm20_20_23 & l_simm20_00_16
    [ value = sext(((l_simm20_20_23 << 16) | l_simm20_00_16) << 8); ]
    { export *[ram]:4 value; }

# MOVI20 #imm20, Rn           0000nnnniiii0000 iiiiiiiiiiiiiiii     imm → sign extension → Rn
:movi20 imm20, l_rn_24_27       
    is l_opcode_28_31=0b0000 & l_rn_24_27 & l_opcode_16_19=0b0000 & imm20
{
    l_rn_24_27 = imm20;
}

# MOVI20S #imm20, Rn          0000nnnniiii0001 iiiiiiiiiiiiiiii     imm<<8 → sign extension → Rn
:movi20s imm20s, l_rn_24_27       
    is l_opcode_28_31=0b0000 & l_rn_24_27 & l_opcode_16_19=0b0001 & imm20s
{
    l_rn_24_27 = imm20s;
}

And the compilation result is as follows:

Compiling ./data/languages/sh-2a.slaspec:
superh.sinc line 352: no viable alternative on : 'value':

    [ value = sext((l_simm20_20_23 << 16) | l_simm20_00_16); ]
------^

superh.sinc line 352: no viable alternative on : '|':

    [ value = sext((l_simm20_20_23 << 16) | l_simm20_00_16); ]
------------------------------------------^

No output produced

Removing sext compiles...

[loudinthecloud]

Thanks, seems that sext is not needed at all if the token is signed.