elna/boot/symbol.s

280 lines
5.8 KiB
ArmAsm

# This Source Code Form is subject to the terms of the Mozilla Public License,
# v. 2.0. If a copy of the MPL was not distributed with this file, You can
# obtain one at https://mozilla.org/MPL/2.0/.
.global symbol_table
.global symbol_table_build, symbol_table_find, symbol_table_insert, symbol_table_dump
.global symbol_table_make_pointer, symbol_table_make_parameter, symbol_table_make_local
.include "boot/definitions.inc"
.equ SYMBOL_PRIME, 1543
.section .rodata
.type symbol_builtin_name_int, @object
symbol_builtin_name_int: .ascii "Int"
.type symbol_builtin_name_word, @object
symbol_builtin_name_word: .ascii "Word"
.type symbol_builtin_name_byte, @object
symbol_builtin_name_byte: .ascii "Byte"
.type symbol_builtin_name_char, @object
symbol_builtin_name_char: .ascii "Char"
.type symbol_builtin_name_bool, @object
symbol_builtin_name_bool: .ascii "Bool"
# Every type info starts with a word describing what type it is.
# Primitive types have only type size.
.type symbol_builtin_type_int, @object
symbol_builtin_type_int: .word TYPE_PRIMITIVE
.word 4
.type symbol_builtin_type_word, @object
symbol_builtin_type_word: .word TYPE_PRIMITIVE
.word 4
.type symbol_builtin_type_byte, @object
symbol_builtin_type_byte: .word TYPE_PRIMITIVE
.word 1
.type symbol_builtin_type_char, @object
symbol_builtin_type_char: .word TYPE_PRIMITIVE
.word 1
.type symbol_builtin_type_bool, @object
symbol_builtin_type_bool: .word TYPE_PRIMITIVE
.word 1
.section .bss
# The first word of the symbol table is its length.
# Then a list of type infos follows:
#
# record
# name: String
# info: ^TypeInfo
# end
.type symbol_table, @object
symbol_table: .zero SYMBOL_PRIME
.section .text
# Prints the list of symbols in the table.
.type symbol_table_dump, @function
symbol_table_dump:
# Prologue.
addi sp, sp, -32
sw ra, 28(sp)
sw s0, 24(sp)
addi s0, sp, 32
sw s1, 20(sp) # Current symbol in the table.
sw s2, 16(sp) # Symbol table length.
la s1, symbol_table
lw s2, 0(s1)
addi s1, s1, 4 # Advance to the first symbol in the table.
.Lsymbol_table_dump_loop:
beqz s2, .Lsymbol_table_dump_end
# Compare string lengths.
lw a0, 4(s1)
lw a1, 0(s1)
call _write_error
addi s1, s1, 12
addi s2, s2, -1
j .Lsymbol_table_dump_loop
.Lsymbol_table_dump_end:
lw s1, 20(sp)
lw s2, 16(sp)
# Epilogue.
lw ra, 28(sp)
lw s0, 24(sp)
addi sp, sp, 32
ret
# Searches for a symbol by name.
#
# Parameters:
# a0 - Length of the symbol to search.
# a1 - Pointer to the symbol name.
#
# Sets a0 to the symbol info pointer or 0 if the symbol has not been found.
.type symbol_table_find, @function
symbol_table_find:
# Prologue.
addi sp, sp, -32
sw ra, 28(sp)
sw s0, 24(sp)
addi s0, sp, 32
sw s1, 20(sp) # Current symbol in the table.
sw s2, 16(sp) # Symbol table length.
sw s3, 12(sp) # Length of the symbol to search.
sw s4, 8(sp) # Pointer to the symbol to search.
mv s3, a0
mv s4, a1
la s1, symbol_table
lw s2, 0(s1)
addi s1, s1, 4 # Advance to the first symbol in the table.
.Lsymbol_table_find_loop:
beqz s2, .Lsymbol_table_find_not_found
# Compare string lengths.
mv a0, s3
mv a1, s4
lw a2, 0(s1)
lw a3, 4(s1)
call _string_equal
beqz a0, .Lsymbol_table_find_continue
lw a0, 8(s1) # Pointer to the symbol.
j .Lsymbol_table_find_end
.Lsymbol_table_find_continue:
addi s1, s1, 12
addi s2, s2, -1
j .Lsymbol_table_find_loop
.Lsymbol_table_find_not_found:
li a0, 0
.Lsymbol_table_find_end:
lw s1, 20(sp)
lw s2, 16(sp)
lw s3, 12(sp)
lw s4, 8(sp)
# Epilogue.
lw ra, 28(sp)
lw s0, 24(sp)
addi sp, sp, 32
ret
# Creates a pointer type.
#
# Parameters:
# a0 - Pointer to the base type.
# a1 - Output memory.
#
# Sets a0 to the size of newly created type in bytes.
.type symbol_table_make_pointer, @function
symbol_table_make_pointer:
li t0, TYPE_POINTER
sw t0, 0(a1)
sw a0, 4(a1)
li a0, 8
ret
# Creates a parameter info.
#
# Parameters:
# a0 - Pointer to the parameter type.
# a1 - Parameter offset.
# a2 - Output memory.
#
# Sets a0 to the size of newly created info object in bytes.
.type symbol_table_make_parameter, @function
symbol_table_make_parameter:
li t0, INFO_PARAMETER
sw t0, 0(a2)
sw a0, 4(a2)
sw a1, 8(a2)
li a0, 12
ret
# Creates a local variable info.
#
# Parameters:
# a0 - Pointer to the variable type.
# a1 - Variable stack offset.
# a2 - Output memory.
#
# Sets a0 to the size of newly created info object in bytes.
.type symbol_table_make_local, @function
symbol_table_make_local:
li t0, INFO_LOCAL
sw t0, 0(a2)
sw a0, 4(a2)
sw a1, 8(a2)
li a0, 12
ret
# Inserts a symbol into the table.
#
# Parameters:
# a0 - Symbol name length.
# a1 - Symbol name pointer.
# a2 - Symbol pointer.
.type symbol_table_insert, @function
symbol_table_insert:
la t0, symbol_table
lw t1, 0(t0) # Current table length.
li t2, 12 # Calculate the offset to the next entry.
mul t2, t1, t2
addi t2, t2, 4
add t2, t0, t2
sw a0, 0(t2)
sw a1, 4(t2)
sw a2, 8(t2)
addi t1, t1, 1 # Save the new length.
sw t1, 0(t0)
ret
# Build the initial symbols.
#
# Sets a0 to the pointer to the global symbol table.
.type symbol_build, @function
symbol_table_build:
# Prologue.
addi sp, sp, -16
sw ra, 12(sp)
sw s0, 8(sp)
addi s0, sp, 16
la a0, symbol_table
addi t0, a0, 4
li a0, 3 # Length of the word "Int".
la a1, symbol_builtin_name_int
la a2, symbol_builtin_type_int
call symbol_table_insert
li a0, 4 # Length of the word "Word".
la a1, symbol_builtin_name_word
la a2, symbol_builtin_type_word
call symbol_table_insert
li a0, 4 # Length of the word "Byte".
la a1, symbol_builtin_name_byte
la a2, symbol_builtin_type_byte
call symbol_table_insert
li a0, 4 # Length of the word "Char".
la a1, symbol_builtin_name_char
la a2, symbol_builtin_type_char
call symbol_table_insert
li a0, 4 # Length of the word "Bool".
la a1, symbol_builtin_name_bool
la a2, symbol_builtin_type_bool
call symbol_table_insert
# Epilogue.
lw ra, 12(sp)
lw s0, 8(sp)
addi sp, sp, 16
ret