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assembler: emit ADD (Shifted Register) instructions

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Signed-off-by: Ronald Caesar <github43132@proton.me>
This commit is contained in:
Ronald Caesar
2026-06-06 06:41:53 -04:00
parent 4c7e7cd58f
commit c0a47775ec
2 changed files with 112 additions and 2 deletions
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include/bal_assembler.h
+17
View File
@@ -95,6 +95,23 @@ extern "C"
uint16_t imm12,
uint8_t shift);
/// Emits a `ADD` (Shifted Register) instruction.
///
/// Adds a register value `rn` and a shifted register `rm`, and writes the result to `rd`.
///
/// # Safety
///
/// * `rd`, `rn`, `rm` must be valid registers (0-31).
/// * `shift` must be between 0 and 63.
/// * `shift_type` must be 0 (LSL), 1 (LSR), or 2 (ASR).
/// * Function does not emit instructions if `assembler->status` != [`BAL_SUCCESS`].
void bal_emit_add_shifted_register(bal_assembler_t *assembler,
bal_register_index_t rd,
bal_register_index_t rn,
bal_register_index_t rm,
uint8_t shift,
uint8_t shift_type);
/// Emits a `B` (Branch) instruction.
///
/// Branches unconditionally to a PC-relative offset.
src/bal_assembler.c
+95 -2
View File
@@ -104,6 +104,98 @@ bal_emit_add_immediate(bal_assembler_t *assembler,
assembler->buffer[assembler->offset++] = instruction;
}
void
bal_emit_add_shifted_register(bal_assembler_t *assembler,
bal_register_index_t rd,
bal_register_index_t rn,
bal_register_index_t rm,
uint8_t shift,
uint8_t shift_type)
{
if (BAL_UNLIKELY(NULL == assembler))
{
return;
}
if (BAL_UNLIKELY(NULL == assembler->buffer))
{
BAL_LOG_ERROR(&assembler->logger, "Aborting function: assembler->buffer is NULL");
assembler->status = BAL_ERROR_INVALID_ARGUMENT;
return;
}
if (BAL_UNLIKELY(assembler->status != BAL_SUCCESS))
{
BAL_LOG_ERROR(&assembler->logger, "Aborting function: assembler->status != BAL_SUCCESS");
return;
}
const bool can_emit_return_value = can_emit(assembler);
if (BAL_UNLIKELY(false == can_emit_return_value))
{
return;
}
if (BAL_UNLIKELY(rd > 31))
{
BAL_LOG_ERROR(&assembler->logger, "Rd X%u out of range (0-31).", rd);
assembler->status = BAL_ERROR_INVALID_ARGUMENT;
return;
}
if (BAL_UNLIKELY(rn > 31))
{
BAL_LOG_ERROR(&assembler->logger, "Rn X%u out of range (0-31).", rn);
assembler->status = BAL_ERROR_INVALID_ARGUMENT;
return;
}
if (BAL_UNLIKELY(rm > 31))
{
BAL_LOG_ERROR(&assembler->logger, "Rm X%u out of range (0-31).", rm);
assembler->status = BAL_ERROR_INVALID_ARGUMENT;
return;
}
if (BAL_UNLIKELY(shift > 63))
{
BAL_LOG_ERROR(&assembler->logger, "%u is not a valid shift amount (0-63).", shift);
assembler->status = BAL_ERROR_INVALID_ARGUMENT;
return;
}
if (BAL_UNLIKELY(shift_type > 2))
{
BAL_LOG_ERROR(&assembler->logger, "%u is not a valid shift type (0-2).", shift_type);
assembler->status = BAL_ERROR_INVALID_ARGUMENT;
return;
}
const uint32_t sf = 1U;
const uint32_t opcode = 0x0BU;
uint32_t instruction = 0;
instruction |= sf << 31;
instruction |= opcode << 24;
instruction |= (uint32_t)shift_type << 22;
instruction |= (uint32_t)rm << 16;
instruction |= (uint32_t)rn << 5;
instruction |= (uint32_t)rd;
const char *mnemonic = "ADD (Shifted Register)";
BAL_LOG_TRACE(&assembler->logger,
"[+0X%04zx] %08x %s X%u, X%u, X%u, shift %u",
assembler->offset * sizeof(uint32_t),
instruction,
mnemonic,
rd,
rn,
rm,
shift);
(void)mnemonic;
assembler->buffer[assembler->offset++] = instruction;
}
void
bal_emit_b(bal_assembler_t *assembler, const int32_t offset)
{
@@ -367,8 +459,9 @@ can_emit(bal_assembler_t *assembler)
{
if (assembler->offset >= assembler->capacity)
{
BAL_LOG_ERROR(
&assembler->logger, "Assembler Overflow. Capacity %zu reached.", assembler->capacity);
BAL_LOG_ERROR(&assembler->logger,
"Aborting function: Assembler Overflow. Capacity %zu reached.",
assembler->capacity);
assembler->status = BAL_ERROR_INSTRUCTION_OVERFLOW;
return false;
}