Compile procedure calls

This commit is contained in:
2025-04-24 23:01:12 +02:00
parent f343296463
commit 2e0c958aa3
4 changed files with 812 additions and 185 deletions

View File

@@ -9,6 +9,293 @@ var
.section .text
# Evalutes an expression and saves the result in a0.
proc _build_expression()
begin
_skip_spaces()
call _read_token
sw s1, 20(sp)
sw a0, 16(sp)
# Integer literal.
addi a0, s1, 0
lb a0, (a0)
call _is_digit
bnez a0, .Lbuild_expression_number_literal
# Named identifier.
li t0, 0x202c30 # 0,_
sw t0, 12(sp)
li t0, 0x6120616c # la a
sw t0, 8(sp)
addi a0, sp, 8
li a1, 7
call _write_out
lw a0, 20(sp)
lw a1, 16(sp)
call _write_out
li t0, 0x0a # \n
sw t0, 12(sp)
addi a0, sp, 12
li a1, 1
call _write_out
j .Lbuild_expression_end
.Lbuild_expression_number_literal:
li t0, 0x202c30 # 0,_
sw t0, 12(sp)
li t0, 0x6120696c # li a
sw t0, 8(sp)
addi a0, sp, 8
li a1, 7
call _write_out
lw a0, 20(sp)
lw a1, 16(sp)
call _write_out
li t0, 0x0a # \n
sw t0, 12(sp)
addi a0, sp, 12
li a1, 1
call _write_out
j .Lbuild_expression_end
.Lbuild_expression_end:
lw a0, 16(sp)
add s1, s1, a0
end
# Compiles a statement beginning with an identifier.
#
# Left values should be variables named "loca n", where n is the offset
# of the variable on the stack, like loca8 or loca4.
proc _compile_identifier()
begin
call _read_token
# Save the pointer to the identifier and its length on the stack.
sw s1, 20(sp)
sw a0, 16(sp)
add s1, s1, a0
_skip_spaces()
call _read_token
# Save the pointer and the length of the token following the identifier.
sw s1, 12(sp)
sw a0, 8(sp)
add s1, s1, a0 # Skip that token.
_skip_spaces()
li t0, 0x3d3a # :=
sw t0, 4(sp)
lw a0, 12(sp)
lw a1, 8(sp)
addi a2, sp, 4
call _token_compare
beqz a0, .Lcompile_identifier_assign
/* DEBUG
mv a0, s1
li a1, 4
call _write_error */
lw t0, 12(sp)
lbu t0, (t0)
li t1, 0x28 # (
beq t0, t1, .Lcompile_identifier_call
j .Lcompile_identifier_end
.Lcompile_identifier_call:
lw a0, 20(sp)
lw a1, 16(sp)
call _compile_call
j .Lcompile_identifier_end
.Lcompile_identifier_assign:
call _build_expression
li t0, 0x202c30 # 0,_
sw t0, 12(sp)
li t0, 0x61207773 # sw a
sw t0, 8(sp)
addi a0, sp, 8
li a1, 7
call _write_out
lw a0, 20(sp)
lw a1, 16(sp)
addi a0, a0, 4 # Skip the "loca" variable prefix.
addi a1, a1, -4 # Skip the "loca" variable prefix.
call _write_out
li t0, 0x0a # \n
sw t0, 12(sp)
li t0, 0x29707328 # (sp)
sw t0, 8(sp)
addi a0, sp, 8
li a1, 5
call _write_out
j .Lcompile_identifier_end
.Lcompile_identifier_end:
end
# Compiles a procedure call. Expects s1 to point to the first argument.
# a0 - Pointer to the procedure name.
# a1 - Length of the procedure name.
#
# Returns the procedure result in a0.
proc _compile_call()
begin
sw a0, 20(sp)
sw a1, 16(sp)
sw zero, 12(sp) # Argument count for a procedure call.
.Lcompile_call_paren:
_skip_spaces()
call _read_token
lbu t0, (s1)
li t1, 0x29 # )
beq t0, t1, .Lcompile_call_complete
.Lcompile_call_argument:
call _build_expression
li t0, 0x202c30 # 0,_
sw t0, 8(sp)
li t0, 0x61207773 # sw a
sw t0, 4(sp)
addi a0, sp, 4
li a1, 7
call _write_out
lw t0, 12(sp) # Argument count for a procedure call.
# Only 8 arguments are supported with a0-a7.
# Save all arguments on the stack so they aren't overriden afterwards.
# The offset on the stack always has two digits in this case.
li t1, -4
mul t1, t0, t1
addi t1, t1, 84
li t2, 10
div t3, t1, t2
rem t4, t1, t2
addi t3, t3, '0'
addi t4, t4, '0'
sw t3, 8(sp)
sw t4, 4(sp)
addi a0, sp, 8
li a1, 1
call _write_out
addi a0, sp, 4
li a1, 1
call _write_out
li t0, 0x0a # \n
sw t0, 8(sp)
li t0, 0x29707328 # (sp)
sw t0, 4(sp)
addi a0, sp, 4
li a1, 5
call _write_out
_skip_spaces()
call _read_token
lbu t0, (s1)
li t1, ','
bne t0, t1, .Lcompile_call_paren
lw t0, 12(sp) # Argument count for a procedure call.
addi t0, t0, 1
sw t0, 12(sp)
_advance(1) # Skip the comma between the arguments.
j .Lcompile_call_argument
.Lcompile_call_complete:
sw zero, 12(sp)
.Lcompile_call_restore:
# Just go through all a0-a7 registers and read them from stack.
# If this stack value contains garbage, the procedure just shouldn't use it.
lw t0, 12(sp)
li t1, 7
bgt t0, t1, .Lcompile_call_perform
li t0, 0x6120776c # lw a
sw t0, 4(sp)
addi a0, sp, 4
li a1, 4
call _write_out
lw t0, 12(sp) # Argument count for a procedure call.
li t1, -4
mul t1, t0, t1
addi t1, t1, 84
li t2, 10
div t3, t1, t2
rem t4, t1, t2
addi t3, t3, '0'
addi t4, t4, '0'
addi t0, t0, '0'
li t5, 0x0a # \n
sb t5, 11(sp)
li t5, 0x29707328 # (sp)
sw t5, 7(sp)
sb t4, 6(sp)
sb t3, 5(sp)
li t5, 0x202c # ,_
sh t5, 3(sp)
sb t0, 2(sp)
addi a0, sp, 2
li a1, 10
call _write_out
lw t0, 12(sp) # Increment.
addi t0, t0, 1
sw t0, 12(sp)
j .Lcompile_call_restore
.Lcompile_call_perform:
li t0, 0x20
sw t0, 8(sp)
li t0, 0x6c6c6163
sw t0, 4(sp)
addi a0, sp, 4
li a1, 5
call _write_out
lw a0, 20(sp)
lw a1, 16(sp)
call _write_out
li t0, 0x0a # \n
sw t0, 8(sp)
addi a0, sp, 8
li a1, 1
call _write_out
_skip_spaces()
_advance(1) # Skip the close paren.
end
# Reads a token and returns its length in a0.
# _read_token doesn't change s1, it finds the length of the token s1 is pointing to.
proc _read_token()
@@ -45,7 +332,7 @@ begin
add t1, s1, t6
lbu a0, (t1) # a0 = Current character.
call is_alnum
call _is_alnum
beqz a0, .Ltoken_character_end
lw t6, 4(sp)
@@ -90,7 +377,7 @@ begin
j .Lspace_loop_end
.Lspace_loop_repeat:
addi s1, s1, 1
_advance(1)
j .Lspace_loop_do
.Lspace_loop_end:
@@ -108,7 +395,7 @@ begin
j .Lskip_indentation_end
.Lskip_indentation_skip:
addi s1, s1, 1
_advance(1)
j .Lskip_indentation_do
.Lskip_indentation_end:
@@ -119,7 +406,7 @@ end
proc _skip_comment()
begin
add s1, s1, a0
addi s1, s1, 1 # Skip the new line.
_advance(1) # Skip the new line.
end
# Parameters:
@@ -131,7 +418,7 @@ begin
# Write the source to the standard output.
mv a0, s1
lw a1, 4(sp)
call write_out
call _write_out
lw t0, 4(sp)
add s1, s1, t0
@@ -140,9 +427,9 @@ begin
sb t0, 0(sp)
addi a0, sp, 0
li a1, 1
call write_out
call _write_out
addi s1, s1, 1 # Skip the new line.
_advance(1) # Skip the new line.
end
proc _compile_program()
@@ -159,9 +446,9 @@ begin
addi a0, sp, 8
li a1, 15
call write_out
call _write_out
addi s1, s1, 8 # program\n.
_advance(8) # program\n.
end
proc _compile_constant_section()
@@ -180,14 +467,14 @@ begin
addi a0, sp, 4
li a1, 17
call write_out
call _write_out
addi s1, s1, 6 # const\n.
_advance(6) # const\n.
.Lcompile_constant_section_item:
call _skip_spaces
_skip_spaces()
lbu a0, (s1)
call is_upper
call _is_upper
beqz a0, .Lcompile_constant_section_end
call _compile_constant
@@ -203,11 +490,11 @@ begin
mv a1, a0 # The identifier length from _read_token should be in a1.
mv a0, s1 # Save the identifier pointer before advancing it.
add s1, s1, a1
call write_out
call _write_out
call _skip_spaces
_skip_spaces()
call _read_token
addi s1, s1, 2 # Skip the assignment sign.
_advance(2) # Skip the assignment sign.
# : .long
li t0, 0x20676e6f # ong_
@@ -216,21 +503,21 @@ begin
sw t0, 0(sp)
mv a0, sp
li a1, 8
call write_out
call _write_out
call _skip_spaces
_skip_spaces()
call _read_token
mv a1, a0 # The literal length from _read_token should be in a1.
mv a0, s1 # Save the literal pointer before advancing it.
add s1, s1, a1
call write_out
call _write_out
li t0, '\n'
sw t0, 4(sp)
addi a0, sp, 4
li a1, 1
call write_out
call _write_out
end
proc _compile_variable_section()
@@ -247,14 +534,14 @@ begin
addi a0, sp, 0
li a1, 14
call write_out
call _write_out
addi s1, s1, 4 # var\n.
_advance(4) # var\n.
.Lcompile_variable_section_item:
call _skip_spaces
_skip_spaces()
lbu a0, (s1)
call is_lower
call _is_lower
beqz a0, .Lcompile_variable_section_end
call _compile_variable
@@ -272,11 +559,11 @@ begin
sw a0, 24(sp)
add s1, s1, a0
call _skip_spaces
addi s1, s1, 1 # Skip the colon in front of the type.
_skip_spaces()
_advance(1) # Skip the colon in front of the type.
call _skip_spaces
addi s1, s1, 1 # Skip the opening bracket.
_skip_spaces()
_advance(1) # Skip the opening bracket.
call _read_token
@@ -285,10 +572,10 @@ begin
sw a0, 16(sp)
add s1, s1, a0
call _skip_spaces
addi s1, s1, 1 # Skip the closing bracket.
_skip_spaces()
_advance(1) # Skip the closing bracket.
call _skip_spaces
_skip_spaces()
call _read_token
add s1, s1, a0 # Skip the type.
@@ -299,11 +586,11 @@ begin
sw t0, 8(sp)
addi a0, sp, 8
li a1, 6
call write_out
call _write_out
lw a0, 28(sp)
lw a1, 24(sp)
call write_out
call _write_out
li t0, 0x0a74 # t\n
sw t0, 12(sp)
@@ -313,7 +600,7 @@ begin
sw t0, 4(sp)
addi a0, sp, 4
li a1, 10
call write_out
call _write_out
# .size identifier, size
li t0, 0x2065 # e_
@@ -322,32 +609,32 @@ begin
sw t0, 8(sp)
addi a0, sp, 8
li a1, 6
call write_out
call _write_out
lw a0, 28(sp)
lw a1, 24(sp)
call write_out
call _write_out
li t0, 0x202c # ,
sw t0, 12(sp)
addi a0, sp, 12
li a1, 2
call write_out
call _write_out
lw a0, 20(sp)
lw a1, 16(sp)
call write_out
call _write_out
li t0, 0x0a # \n
sw t0, 12(sp)
addi a0, sp, 12
li a1, 1
call write_out
call _write_out
# identifier: .zero size
lw a0, 28(sp)
lw a1, 24(sp)
call write_out
call _write_out
li t0, 0x206f7265 # ero_
sw t0, 12(sp)
@@ -355,22 +642,22 @@ begin
sw t0, 8(sp)
addi a0, sp, 8
li a1, 8
call write_out
call _write_out
lw a0, 20(sp)
lw a1, 16(sp)
call write_out
call _write_out
li t0, 0x0a # \n
sw t0, 12(sp)
addi a0, sp, 12
li a1, 1
call write_out
call _write_out
end
proc _compile_procedure()
begin
addi s1, s1, 5 # Skip proc_
_advance(5) # Skip proc_
call _read_token
sw s1, 20(sp)
sw a0, 16(sp)
@@ -383,11 +670,11 @@ begin
sw t0, 8(sp)
addi a0, sp, 8
li a1, 6
call write_out
call _write_out
lw a0, 20(sp)
lw a1, 16(sp)
call write_out
call _write_out
li t0, 0x0a6e6f69 # ion\n
sw t0, 12(sp)
@@ -397,22 +684,22 @@ begin
sw t0, 4(sp)
addi a0, sp, 4
li a1, 12
call write_out
call _write_out
lw a0, 20(sp)
lw a1, 16(sp)
call write_out
call _write_out
li t0, 0x0a3a # :\n
sw t0, 12(sp)
addi a0, sp, 12
li a1, 2
call write_out
call _write_out
call _skip_spaces
addi s1, s1, 1 # Skip opening argument paren.
call _skip_spaces
addi s1, s1, 1 # Skip closing argument paren.
_skip_spaces()
_advance(1) # Skip opening argument paren.
_skip_spaces()
_advance(1) # Skip closing argument paren.
li t0, 0x6e # n
sw t0, 12(sp)
@@ -422,7 +709,7 @@ begin
# Skip all declarations until we find the "begin" keyword, denoting the
# beginning of the procedure body.
.Lcompile_procedure_begin:
call _skip_spaces
_skip_spaces()
call _read_token
mv a1, a0
@@ -438,24 +725,24 @@ begin
sw t0, 12(sp)
addi a0, sp, 12
li a1, 4
call write_out
call _write_out
li t0, 0x2c707320 # _sp,
sw t0, 12(sp)
addi a0, sp, 12
li a1, 4
call write_out
call _write_out
addi a0, sp, 12
li a1, 4
call write_out
call _write_out
li t0, 0x0a36392d # -96\n
sw t0, 12(sp)
addi a0, sp, 12
li a1, 4
call write_out
call _write_out
li t0, 0x0a29 # )\n
sw t0, 12(sp)
@@ -467,7 +754,7 @@ begin
sw t0, 0(sp)
addi a0, sp, 0
li a1, 14
call write_out
call _write_out
li t0, 0x0a29 # )\n
sw t0, 12(sp)
@@ -479,7 +766,7 @@ begin
sw t0, 0(sp)
addi a0, sp, 0
li a1, 14
call write_out
call _write_out
li t0, 0x0a363920 # _96\n
sw t0, 12(sp)
@@ -491,11 +778,11 @@ begin
sw t0, 0(sp)
addi a0, sp, 0
li a1, 16
call write_out
call _write_out
# Generate the body of the procedure.
.Lcompile_procedure_body:
call _skip_indentation
_skip_indentation()
call _read_line
sw a0, 12(sp)
li t0, 0x0a646e65 # end\n
@@ -503,7 +790,7 @@ begin
mv a0, s1
addi a1, sp, 8
li a2, 4
call memcmp
call _memcmp
beqz a0, .Lcompile_procedure_end
@@ -525,7 +812,7 @@ begin
sw t0, 0(sp)
addi a0, sp, 0
li a1, 14
call write_out
call _write_out
li t0, 0x0a29 # )\n
sw t0, 12(sp)
@@ -537,36 +824,36 @@ begin
sw t0, 0(sp)
addi a0, sp, 0
li a1, 14
call write_out
call _write_out
li t0, 0x69646461 # addi
sw t0, 12(sp)
addi a0, sp, 12
li a1, 4
call write_out
call _write_out
li t0, 0x2c707320 # _sp,
sw t0, 12(sp)
addi a0, sp, 12
li a1, 4
call write_out
call _write_out
addi a0, sp, 12
li a1, 4
call write_out
call _write_out
li t0, 0x0a3639 # 96\n
sw t0, 12(sp)
addi a0, sp, 12
li a1, 3
call write_out
call _write_out
li t0, 0x0a746572 # ret\n
sw t0, 12(sp)
addi a0, sp, 12
li a1, 4
call write_out
call _write_out
end
# Compares two string, which of one has a length, the other one is null-terminated.
@@ -632,7 +919,7 @@ begin
mv a0, s1
addi a1, sp, 12
li a2, 8
call memcmp
call _memcmp
beqz a0, .Lcompile_line_program
li t0, 0x0a74 # t\n
@@ -642,7 +929,7 @@ begin
mv a0, s1
addi a1, sp, 12
li a2, 6
call memcmp
call _memcmp
beqz a0, .Lcompile_line_const
li t0, 0x0a726176 # var\n
@@ -650,7 +937,7 @@ begin
mv a0, s1
addi a1, sp, 16
li a2, 4
call memcmp
call _memcmp;
beqz a0, .Lcompile_line_var
li t0, 0x20 # _
@@ -660,7 +947,7 @@ begin
mv a0, s1
addi a1, sp, 12
li a2, 5
call memcmp
call _memcmp
beqz a0, .Lcompile_line_procedure
li t0, 0x0a6e # n\n
@@ -670,7 +957,7 @@ begin
mv a0, s1
addi a1, sp, 12
li a2, 6
call memcmp
call _memcmp
beqz a0, .Lcompile_line_begin
li t0, 0x2e646e65 # end.
@@ -678,11 +965,27 @@ begin
mv a0, s1
addi a1, sp, 16
li a2, 4
call memcmp
call _memcmp
beqz a0, .Lcompile_line_exit
li t0, 0x61636f6c # loca
sw t0, 16(sp)
mv a0, s1
addi a1, sp, 16
li a2, 4
call _memcmp
beqz a0, .Lcompile_line_identifier
lbu t0, (s1)
li t1, '_'
beq t0, t1, .Lcompile_line_identifier
j .Lcompile_line_unchanged # Else.
.Lcompile_line_identifier:
call _compile_identifier
j .Lcompile_line_section
.Lcompile_line_exit:
call _compile_exit
j .Lcompile_line_section
@@ -702,12 +1005,6 @@ begin
j .Lcompile_line_end
.Lcompile_line_var:
/* DEBUG
mv a0, s1
li a1, 20
call write_error */
call _compile_variable_section
j .Lcompile_line_section
@@ -721,7 +1018,7 @@ begin
j .Lcompile_line_section
.Lcompile_line_empty:
addi s1, s1, 1
_advance(1)
j .Lcompile_line_section
.Lcompile_line_unchanged:
@@ -749,7 +1046,7 @@ begin
addi a0, sp, 0
li a1, 15
call write_out
call _write_out
end
proc _compile_entry_point()
@@ -773,9 +1070,9 @@ begin
sw t0, 24(sp)
addi a0, sp, 24
li a1, 32
call write_out
call _write_out
addi s1, s1, 6 # Skip begin\n.
_advance(6) # Skip begin\n.
end
proc _compile_exit()
@@ -799,10 +1096,10 @@ begin
sw t0, 28(sp)
addi a0, sp, 28
li a1, 25
call write_out
call _write_out
addi s1, s1, 4 # Skip end.
call _skip_spaces # Read the possible new line at the end of the file.
_advance(4) # Skip end.
_skip_spaces() # Read the possible new line at the end of the file.
end
# Finds the end of the line and returns its length in a0.
@@ -829,7 +1126,7 @@ begin
lbu t0, (s1) # t0 = Current character.
beqz t0, .Lcompile_end # Exit the loop on the NUL character.
call _skip_indentation
_skip_indentation()
call _read_line
call _compile_line
@@ -837,13 +1134,25 @@ begin
.Lcompile_end:
end
# Returns the pointer to the current position in the source text in a0.
proc _current()
begin
mv a0, s1
end
# a0 is the number of bytes to advance in the source text.
proc _advance()
begin
add s1, s1, a0
end
# Entry point.
begin
# Read the source from the standard input.
la a0, source_code
la a1, SOURCE_BUFFER_SIZE # Buffer size.
lw a1, (a1)
call read_file
call _read_file
la s1, source_code # s1 = Source code position.
call _compile