espressif/binutils-gdb
1
0
Fork 0
mirror of https://github.com/espressif/binutils-gdb.git synced 2025-06-19 17:18:24 +08:00
Code Issues Packages Projects Releases Wiki Activity

RISC-V: Add support for arbitrary immediate encoding formats

Browse Source 
This patch introduces support for arbitrary signed or unsigned immediate
encoding formats. The formats have the form "XsN@S" and "XuN@S" with N
being the number of bits and S the LSB position.

For example an immediate field of 5 bytes that encodes a signed value
and is stored in the bits 24-20 of the instruction word can use the
format specifier "Xs5@20".

Co-developed-by: Lifang Xia <lifang_xia@linux.alibaba.com>
Signed-off-by: Christoph Müllner <christoph.muellner@vrull.eu>
This commit is contained in:
Christoph Müllner
2022-06-28 17:44:15 +02:00
committed by Philipp Tomsich
parent 547c18d9bb
commit 8b7419c429
3 changed files with 125 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

74
gas/config/tc-riscv.c
View File

@ -452,6 +452,9 @@ static char *expr_end;
#define INSERT_OPERAND(FIELD, INSN, VALUE) \
INSERT_BITS ((INSN).insn_opcode, VALUE, OP_MASK_##FIELD, OP_SH_##FIELD)
#define INSERT_IMM(n, s, INSN, VALUE) \
INSERT_BITS ((INSN).insn_opcode, VALUE, (1ULL<<n) - 1, s)
/* Determine if an instruction matches an opcode. */
#define OPCODE_MATCHES(OPCODE, OP) \
(((OPCODE) & MASK_##OP) == MATCH_##OP)
@ -1103,6 +1106,8 @@ arg_lookup (char **s, const char *const *array, size_t size, unsigned *regnop)
}
#define USE_BITS(mask,shift) (used_bits |= ((insn_t)(mask) << (shift)))
#define USE_IMM(n, s) \
(used_bits |= ((insn_t)((1ull<<n)-1) << (s)))
/* For consistency checking, verify that all bits are specified either
by the match/mask part of the instruction definition, or by the
@ -1267,6 +1272,31 @@ validate_riscv_insn (const struct riscv_opcode *opc, int length)
goto unknown_validate_operand;
}
break;
case 'X': /* Integer immediate. */
{
size_t n;
size_t s;
switch (*++oparg)
{
case 's': /* 'XsN@S' ... N-bit signed immediate at bit S. */
goto use_imm;
case 'u': /* 'XuN@S' ... N-bit unsigned immediate at bit S. */
goto use_imm;
use_imm:
n = strtol (++oparg, (char **)&oparg, 10);
if (*oparg != '@')
goto unknown_validate_operand;
s = strtol (++oparg, (char **)&oparg, 10);
oparg--;
USE_IMM (n, s);
break;
default:
goto unknown_validate_operand;
}
}
break;
default:
unknown_validate_operand:
as_bad (_("internal: bad RISC-V opcode "
@ -3272,6 +3302,50 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
asarg = expr_end;
continue;
case 'X': /* Integer immediate. */
{
size_t n;
size_t s;
bool sign;
switch (*++oparg)
{
case 's': /* 'XsN@S' ... N-bit signed immediate at bit S. */
sign = true;
goto parse_imm;
case 'u': /* 'XuN@S' ... N-bit unsigned immediate at bit S. */
sign = false;
goto parse_imm;
parse_imm:
n = strtol (++oparg, (char **)&oparg, 10);
if (*oparg != '@')
goto unknown_riscv_ip_operand;
s = strtol (++oparg, (char **)&oparg, 10);
oparg--;
my_getExpression (imm_expr, asarg);
check_absolute_expr (ip, imm_expr, false);
if (!sign)
{
if (!VALIDATE_U_IMM (imm_expr->X_add_number, n))
as_bad (_("improper immediate value (%lu)"),
(unsigned long) imm_expr->X_add_number);
}
else
{
if (!VALIDATE_S_IMM (imm_expr->X_add_number, n))
as_bad (_("improper immediate value (%li)"),
(long) imm_expr->X_add_number);
}
INSERT_IMM (n, s, *ip, imm_expr->X_add_number);
imm_expr->X_op = O_absent;
asarg = expr_end;
continue;
default:
goto unknown_riscv_ip_operand;
}
}
break;
default:
unknown_riscv_ip_operand:
as_fatal (_("internal: unknown argument type `%s'"),

17
include/opcode/riscv.h
View File

@ -60,6 +60,7 @@ static const char * const riscv_pred_succ[16] =
#define RV_X(x, s, n) (((x) >> (s)) & ((1 << (n)) - 1))
#define RV_IMM_SIGN(x) (-(((x) >> 31) & 1))
#define RV_X_SIGNED(x, s, n) (RV_X(x, s, n) | ((-(RV_X(x, (s + n - 1), 1))) << (n)))
#define EXTRACT_ITYPE_IMM(x) \
(RV_X(x, 20, 12) | (RV_IMM_SIGN(x) << 12))
@ -347,6 +348,22 @@ static const char * const riscv_pred_succ[16] =
#define EXTRACT_OPERAND(FIELD, INSN) \
EXTRACT_BITS ((INSN), OP_MASK_##FIELD, OP_SH_##FIELD)
/* Extract an unsigned immediate operand on position s with n bits. */
#define EXTRACT_U_IMM(n, s, l) \
RV_X (l, s, n)
/* Extract an signed immediate operand on position s with n bits. */
#define EXTRACT_S_IMM(n, s, l) \
RV_X_SIGNED (l, s, n)
/* Validate that unsigned n-bit immediate is within bounds. */
#define VALIDATE_U_IMM(v, n) \
((unsigned long) v < (1UL << n))
/* Validate that signed n-bit immediate is within bounds. */
#define VALIDATE_S_IMM(v, n) \
(v < (long) (1UL << (n-1)) && v >= -(offsetT) (1UL << (n-1)))
/* The maximal number of subset can be required. */
#define MAX_SUBSET_NUM 4

34
opcodes/riscv-dis.c
View File

@ -562,7 +562,41 @@ print_insn_args (const char *oparg, insn_t l, bfd_vma pc, disassemble_info *info
print (info->stream, dis_style_text, "%d", rs1);
break;
case 'X': /* Integer immediate. */
{
size_t n;
size_t s;
bool sign;
switch (*++oparg)
{
case 's': /* 'XsN@S' ... N-bit signed immediate at bit S. */
sign = true;
goto print_imm;
case 'u': /* 'XuN@S' ... N-bit unsigned immediate at bit S. */
sign = false;
goto print_imm;
print_imm:
n = strtol (++oparg, (char **)&oparg, 10);
if (*oparg != '@')
goto undefined_modifier;
s = strtol (++oparg, (char **)&oparg, 10);
oparg--;
if (!sign)
print (info->stream, dis_style_immediate, "%u",
(unsigned)EXTRACT_U_IMM (n, s, l));
else
print (info->stream, dis_style_immediate, "%i",
(unsigned)EXTRACT_S_IMM (n, s, l));
break;
default:
goto undefined_modifier;
}
}
break;
default:
undefined_modifier:
/* xgettext:c-format */
print (info->stream, dis_style_text,
_("# internal error, undefined modifier (%c)"),