fsw
Single-precision floating-point store
This instruction is defined by:
-
F, version >= 0
This instruction is included in the following profiles:
-
RVA20U64 (Mandatory)
-
RVA22U64 (Mandatory)
-
RVI20U32 (Optional)
-
RVI20U64 (Optional)
Synopsis
| This instruction must have data-independent timing when extension Zkt is enabled. |
The fsw instruction stores a single-precision floating-point value in fs2 to memory at address rs1 + imm.
fsw does not modify the bits being transferred; in particular, the payloads of non-canonical NaNs are preserved.
Decode Variables
Bits<12> imm = {$encoding[31:25], $encoding[11:7]};
Bits<5> fs2 = $encoding[24:20];
Bits<5> rs1 = $encoding[19:15];Execution
-
IDL
-
Sail
check_f_ok($encoding);
XReg virtual_address = X[rs1] + $signed(imm);
write_memory<32>(virtual_address, f[fs2][31:0], $encoding);{
let offset : xlenbits = sign_extend(imm);
let (aq, rl, con) = (false, false, false);
/* Get the address, X(rs1) + offset.
Some extensions perform additional checks on address validity. */
match ext_data_get_addr(rs1, offset, Write(Data), width) {
Ext_DataAddr_Error(e) => { ext_handle_data_check_error(e); RETIRE_FAIL },
Ext_DataAddr_OK(vaddr) =>
if check_misaligned(vaddr, width)
then { handle_mem_exception(vaddr, E_SAMO_Addr_Align()); RETIRE_FAIL }
else match translateAddr(vaddr, Write(Data)) {
TR_Failure(e, _) => { handle_mem_exception(vaddr, e); RETIRE_FAIL },
TR_Address(addr, _) => {
let eares : MemoryOpResult(unit) = match width {
BYTE => MemValue () /* bogus placeholder for illegal size */,
HALF => mem_write_ea(addr, 2, aq, rl, false),
WORD => mem_write_ea(addr, 4, aq, rl, false),
DOUBLE => mem_write_ea(addr, 8, aq, rl, false)
};
match (eares) {
MemException(e) => { handle_mem_exception(vaddr, e); RETIRE_FAIL },
MemValue(_) => {
let rs2_val = F(rs2);
match (width) {
BYTE => { handle_illegal(); RETIRE_FAIL },
HALF => process_fstore (vaddr, mem_write_value(addr, 2, rs2_val[15..0], aq, rl, con)),
WORD => process_fstore (vaddr, mem_write_value(addr, 4, rs2_val[31..0], aq, rl, con)),
DOUBLE if sizeof(flen) >= 64 =>
process_fstore (vaddr, mem_write_value(addr, 8, rs2_val, aq, rl, con)),
_ => report_invalid_width(__FILE__, __LINE__, width, "floating point store"),
};
}
}
}
}
}
}