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riscv: Use GAS syntax for loads/stores:
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Before:
    ld rd, rs, imm
    sd rs1, rs2, imm

Now:
    ld rd, imm(rs)
    sd rs2, imm(rs1)

NOTES: Just as in GAS:
    - In stores the register order is swapped
    - imm is optional
    - when imm is not included parenthesis can be removed
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@ekaitz-zarraga
ekaitz-zarraga committed Mar 19, 2024
1 parent 019d10f commit 8cbbd2b
Showing 1 changed file with 98 additions and 51 deletions.
149 changes: 98 additions & 51 deletions riscv64-asm.c
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Original file line number Diff line number Diff line change
Expand Up @@ -63,6 +63,7 @@ static void asm_unary_opcode(TCCState *s1, int token);
ST_FUNC void gen_expr32(ExprValue *pe);
static void parse_operand(TCCState *s1, Operand *op);
static void parse_operands(TCCState *s1, Operand *ops, int count);
static void parse_mem_access_operands(TCCState *s1, Operand* ops);
ST_FUNC void subst_asm_operand(CString *add_str, SValue *sv, int modifier);
/* C extension */
static void asm_emit_ca(int token, uint16_t opcode, const Operand *rd, const Operand *rs2);
Expand Down Expand Up @@ -223,6 +224,43 @@ static void parse_operands(TCCState *s1, Operand* ops, int count){
}
}

/* parse `X, imm(Y)` to {X, Y, imm} operands */
static void parse_mem_access_operands(TCCState *s1, Operand* ops){
static const Operand zimm = {.type = OP_IM12S};

Operand op;
int i;

parse_operand(s1, &ops[0]);
if ( tok == ',')
next();
else
expect("','");

if ( tok == '(') {
/* `X, (Y)` case*/
next();
parse_operand(s1, &ops[1]);
if ( tok == ')') next(); else expect("')'");
ops[2] = zimm;
} else {
parse_operand(s1, &ops[2]);
if ( tok == '('){
/* `X, imm(Y)` case*/
next();
parse_operand(s1, &ops[1]);
if ( tok == ')') next(); else expect("')'");
} else {
/* `X, Y` case*/
/* we parsed Y thinking it was imm, swap and default imm to zero */
op = ops[2];
ops[1] = ops[2];
ops[2] = op;
ops[2] = zimm;
}
}
}

static void asm_unary_opcode(TCCState *s1, int token)
{
uint32_t opcode = (0x1C << 2) | 3 | (2 << 12);
Expand Down Expand Up @@ -505,6 +543,52 @@ static void asm_emit_j(int token, uint32_t opcode, const Operand* rd, const Oper
gen_le32(opcode | ENCODE_RD(rd->reg) | (((imm >> 20) & 1) << 31) | (((imm >> 1) & 0x3ff) << 21) | (((imm >> 11) & 1) << 20) | (((imm >> 12) & 0xff) << 12));
}

static void asm_mem_access_opcode(TCCState *s1, int token)
{

Operand ops[3];
parse_mem_access_operands(s1, &ops[0]);

// l{b|h|w|d}[u] rd, imm(rs1); I-format
switch (token) {
case TOK_ASM_lb:
asm_emit_i(token, (0x0 << 2) | 3, &ops[0], &ops[1], &ops[2]);
return;
case TOK_ASM_lh:
asm_emit_i(token, (0x0 << 2) | 3 | (1 << 12), &ops[0], &ops[1], &ops[2]);
return;
case TOK_ASM_lw:
asm_emit_i(token, (0x0 << 2) | 3 | (2 << 12), &ops[0], &ops[1], &ops[2]);
return;
case TOK_ASM_ld:
asm_emit_i(token, (0x0 << 2) | 3 | (3 << 12), &ops[0], &ops[1], &ops[2]);
return;
case TOK_ASM_lbu:
asm_emit_i(token, (0x0 << 2) | 3 | (4 << 12), &ops[0], &ops[1], &ops[2]);
return;
case TOK_ASM_lhu:
asm_emit_i(token, (0x0 << 2) | 3 | (5 << 12), &ops[0], &ops[1], &ops[2]);
return;
case TOK_ASM_lwu:
asm_emit_i(token, (0x0 << 2) | 3 | (6 << 12), &ops[0], &ops[1], &ops[2]);
return;

// s{b|h|w|d} rs2, imm(rs1); S-format (with rsX swapped)
case TOK_ASM_sb:
asm_emit_s(token, (0x8 << 2) | 3 | (0 << 12), &ops[1], &ops[0], &ops[2]);
return;
case TOK_ASM_sh:
asm_emit_s(token, (0x8 << 2) | 3 | (1 << 12), &ops[1], &ops[0], &ops[2]);
return;
case TOK_ASM_sw:
asm_emit_s(token, (0x8 << 2) | 3 | (2 << 12), &ops[1], &ops[0], &ops[2]);
return;
case TOK_ASM_sd:
asm_emit_s(token, (0x8 << 2) | 3 | (3 << 12), &ops[1], &ops[0], &ops[2]);
return;
}
}

static void asm_ternary_opcode(TCCState *s1, int token)
{
Operand ops[3];
Expand Down Expand Up @@ -630,46 +714,6 @@ static void asm_ternary_opcode(TCCState *s1, int token)
asm_emit_b(token, 0x63 | (7 << 12), ops, ops + 1, ops + 2);
return;

// Loads (RD,RS1,I); I-format

case TOK_ASM_lb:
asm_emit_i(token, (0x0 << 2) | 3, &ops[0], &ops[1], &ops[2]);
return;
case TOK_ASM_lh:
asm_emit_i(token, (0x0 << 2) | 3 | (1 << 12), &ops[0], &ops[1], &ops[2]);
return;
case TOK_ASM_lw:
asm_emit_i(token, (0x0 << 2) | 3 | (2 << 12), &ops[0], &ops[1], &ops[2]);
return;
case TOK_ASM_lbu:
asm_emit_i(token, (0x0 << 2) | 3 | (4 << 12), &ops[0], &ops[1], &ops[2]);
return;
case TOK_ASM_lhu:
asm_emit_i(token, (0x0 << 2) | 3 | (5 << 12), &ops[0], &ops[1], &ops[2]);
return;
// 64 bit
case TOK_ASM_ld:
asm_emit_i(token, (0x0 << 2) | 3 | (3 << 12), &ops[0], &ops[1], &ops[2]);
return;
case TOK_ASM_lwu:
asm_emit_i(token, (0x0 << 2) | 3 | (6 << 12), &ops[0], &ops[1], &ops[2]);
return;

// Stores (RS1,RS2,I); S-format

case TOK_ASM_sb:
asm_emit_s(token, (0x8 << 2) | 3 | (0 << 12), &ops[0], &ops[1], &ops[2]);
return;
case TOK_ASM_sh:
asm_emit_s(token, (0x8 << 2) | 3 | (1 << 12), &ops[0], &ops[1], &ops[2]);
return;
case TOK_ASM_sw:
asm_emit_s(token, (0x8 << 2) | 3 | (2 << 12), &ops[0], &ops[1], &ops[2]);
return;
case TOK_ASM_sd:
asm_emit_s(token, (0x8 << 2) | 3 | (3 << 12), &ops[0], &ops[1], &ops[2]);
return;

/* M extension */
case TOK_ASM_div:
asm_emit_r(token, 0x33 | (4 << 12) | (1 << 25), ops, ops + 1, ops + 2);
Expand Down Expand Up @@ -856,6 +900,20 @@ ST_FUNC void asm_opcode(TCCState *s1, int token)
asm_binary_opcode(s1, token);
return;

case TOK_ASM_lb:
case TOK_ASM_lh:
case TOK_ASM_lw:
case TOK_ASM_ld:
case TOK_ASM_lbu:
case TOK_ASM_lhu:
case TOK_ASM_lwu:
case TOK_ASM_sb:
case TOK_ASM_sh:
case TOK_ASM_sw:
case TOK_ASM_sd:
asm_mem_access_opcode(s1, token);
break;

case TOK_ASM_add:
case TOK_ASM_addi:
case TOK_ASM_addiw:
Expand All @@ -869,18 +927,8 @@ ST_FUNC void asm_opcode(TCCState *s1, int token)
case TOK_ASM_bltu:
case TOK_ASM_bne:
case TOK_ASM_jalr:
case TOK_ASM_lb:
case TOK_ASM_lbu:
case TOK_ASM_ld:
case TOK_ASM_lh:
case TOK_ASM_lhu:
case TOK_ASM_lw:
case TOK_ASM_lwu:
case TOK_ASM_or:
case TOK_ASM_ori:
case TOK_ASM_sb:
case TOK_ASM_sd:
case TOK_ASM_sh:
case TOK_ASM_sll:
case TOK_ASM_slli:
case TOK_ASM_slliw:
Expand All @@ -899,7 +947,6 @@ ST_FUNC void asm_opcode(TCCState *s1, int token)
case TOK_ASM_srlw:
case TOK_ASM_sub:
case TOK_ASM_subw:
case TOK_ASM_sw:
case TOK_ASM_xor:
case TOK_ASM_xori:
/* M extension */
Expand Down

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