Unify taking an identifier address

boot/stage1.s

@@ -249,31 +249,47 @@ is_local_identifier:
 	addi sp, sp, 16
 	ret
 
-# Checks whether the given identifier is a saved register name, like s1 or s2.
+# Looks for a register that can be used to calculate a symbol address. Writes it
+# as string, like sp or s0 into the provided buffer.
+# 
 # Parameters:
-# a0 - Pointer to the identifier.
-# a1 - Identifier length.
+# a0 - Symbol info pointer.
+# a1 - Output buffer.
 #
-# Sets a0 to 1 if the identifier is a preserved register, otherwise to 0.
-.type is_register_identifier, @function
-is_register_identifier:
-	# Prologue.
-	addi sp, sp, -8
-	sw ra, 4(sp)
-	sw s0, 0(sp)
-	addi s0, sp, 8
+# Sets a0 to the length of register name written or 0.
+.type take_address, @function
+take_address:
+	beqz a0, .Ltake_address_undefined
+	lw t0, 0(a0)
 
-	lbu a0, (a0)
-	addi a1, a1, -2
-	seqz a1, a1
-	addi t0, a0, -'s'
-	seqz t0, t0
-	and a0, a1, t0
+	li t1, INFO_PARAMETER
+	beq t0, t1, .Ltake_address_parameter
 
-	# Epilogue.
-	lw ra, 4(sp)
-	lw s0, 0(sp)
-	addi sp, sp, 8
+	li t1, INFO_LOCAL
+	beq t0, t1, .Ltake_address_local
+
+	j .Ltake_address_undefined
+
+.Ltake_address_parameter:
+	li t0, 0x3073 # s0
+	sh t0, (a1)
+
+	li a0, 2
+
+	j .Ltake_address_end
+
+.Ltake_address_local:
+	li t0, 0x7073 # (sp)
+	sh t0, (a1)
+
+	li a0, 2
+
+	j .Ltake_address_end
+
+.Ltake_address_undefined:
+	li a0, 0
+
+.Ltake_address_end:
 	ret
 
 # Parameters:
@@ -298,18 +314,9 @@ compile_identifier_expression:
 	beqz a0, .Lcompile_identifier_expression_by_name
 	lw t0, 0(a0)
 
-	li t1, INFO_PARAMETER
-	beq t0, t1, .Lcompile_identifier_expression_parameter
-
-	li t1, INFO_LOCAL
-	beq t0, t1, .Lcompile_identifier_expression_local
+	j .Lcompile_identifier_expression_by_address
 
 .Lcompile_identifier_expression_by_name:
-	mv a0, s1
-	lw a1, 20(sp)
-	call is_register_identifier
-	bnez a0, .Lcompile_identifier_expression_saved
-
 	# Global identifier.
 	lw t1, 16(sp)
 	li t0, 0x00202c00 # \0,_
@@ -348,7 +355,7 @@ compile_identifier_expression:
 
 	j .Lcompile_identifier_expression_end
 
-.Lcompile_identifier_expression_parameter:
+.Lcompile_identifier_expression_by_address:
 	lw t1, 16(sp)
 	li t0, 0x00202c00 # \0,_
 	or t0, t0, t1
@@ -363,56 +370,17 @@ compile_identifier_expression:
 	lw a0, 8(a0)
 	call _write_i
 
-	li t0, 0x29307328 # (s0)
-	sw t0, 8(sp)
-	li a0, 4
-	addi a1, sp, 8
-	call _write_s
-	li a0, '\n'
+	li a0, '('
 	call _write_c
 
-	j .Lcompile_identifier_expression_end
-
-.Lcompile_identifier_expression_local:
-	lw t1, 16(sp)
-	li t0, 0x00202c00 # \0,_
-	or t0, t0, t1
-	sw t0, 8(sp)
-	li t0, 0x6120776c # lw a
-	sw t0, 4(sp)
-	li a0, 7
-	addi a1, sp, 4
-	call _write_s
-
 	lw a0, 12(sp)
-	lw a0, 8(a0)
-	call _write_i
-
-	li t0, 0x29707328 # (sp)
-	sw t0, 8(sp)
-	li a0, 4
-	addi a1, sp, 8
-	call _write_s
-	li a0, '\n'
-	call _write_c
-
-	j .Lcompile_identifier_expression_end
-
-.Lcompile_identifier_expression_saved:
-	li t0, 0x00202c00 # \0,_
-	lw t1, 16(sp)
-	or t0, t0, t1
-	sw t0, 8(sp)
-	li t0, 0x6120766d # mv a
-	sw t0, 4(sp)
-	li a0, 7
+	addi a1, sp, 4
+	call take_address
 	addi a1, sp, 4
 	call _write_s
 
-	lw a0, 20(sp)
-	mv a1, s1
-	call _write_s
-
+	li a0, ')'
+	call _write_c
 	li a0, '\n'
 	call _write_c
 
@@ -552,81 +520,36 @@ compile_at_expression:
 	lw a1, 32(sp)
 	call symbol_table_find
 	sw a0, 20(sp)
-	lw t0, 0(a0)
 
-	li t1, INFO_PARAMETER
-	beq t0, t1, .Lcompile_at_expression_parameter
-
-	li t1, INFO_LOCAL
-	beq t0, t1, .Lcompile_at_expression_local
-
-	unimp
-
-.Lcompile_at_expression_local:
-	lw a0, 36(sp)
 	li t0, 0x20 # _
-	sw t0, 16(sp)
-	li t0, 0x2c707320 # _sp,
-	sw t0, 12(sp)
+	sb t0, 12(sp)
+
+	# lw a0, 28(sp)
+	lw a1, 32(sp)
+	addi a1, sp, 13
+	call take_address
+
+	lw t1, 36(sp)
 	li t0, 0x2c006120 # _a\0,
 	sw t0, 8(sp)
-	sb a0, 10(sp)
+	sb t1, 10(sp)
 	li t0, 0x69646461 # addi
 	sw t0, 4(sp)
-	li a0, 13
+	addi a0, a0, 9 # The length returned by take_address + the instruction.
 	addi a1, sp, 4
 	call _write_s
 
+	li a0, ','
+	call _write_c
+	li a0, ' '
+	call _write_c
+
 	lw a0, 20(sp)
 	lw a0, 8(a0)
 	call _write_i
 
 	j .Lcompile_at_expression_end
 
-.Lcompile_at_expression_parameter:
-	lw a0, 36(sp)
-	li t0, 0x20 # _
-	sw t0, 16(sp)
-	li t0, 0x2c307320 # _s0,
-	sw t0, 12(sp)
-	li t0, 0x2c006120 # _a\0,
-	sw t0, 8(sp)
-	sb a0, 10(sp)
-	li t0, 0x69646461 # addi
-	sw t0, 4(sp)
-	li a0, 13
-	addi a1, sp, 4
-	call _write_s
-
-	lw a0, 20(sp)
-	lw a0, 8(a0)
-	call _write_i
-
-	j .Lcompile_at_expression_end
-
-.Lcompile_at_expression_undefined:
-	lw a0, 36(sp)
-	li t0, 0x20 # _
-	sw t0, 16(sp)
-	li t0, 0x2c707320 # _sp,
-	sw t0, 12(sp)
-	li t0, 0x2c006120 # _a\0,
-	sw t0, 8(sp)
-	sb a0, 10(sp)
-	li t0, 0x69646461 # addi
-	sw t0, 4(sp)
-	li a0, 13
-	addi a1, sp, 4
-	call _write_s
-
-	lw a0, 32(sp)
-	lw a1, 28(sp)
-	addi a0, a1, -4 # Skip the "loca" variable prefix.
-	addi a1, a0, 4 # Skip the "loca" variable prefix.
-	call _write_s
-
-	j .Lcompile_at_expression_end
-
 .Lcompile_at_expression_end:
 	li a0, '\n'
 	call _write_c
@@ -658,11 +581,6 @@ compile_designator_expression:
 	call is_local_identifier
 	bnez a0, .Lcompile_designator_expression_local
 
-	lw a0, 20(sp)
-	lw a1, 16(sp)
-	call is_register_identifier
-	bnez a0, .Lcompile_designator_expression_saved
-
 .Lcompile_designator_expression_local:
 	li t0, 0x202c30 # 0,_
 	sw t0, 12(sp)
@@ -688,27 +606,6 @@ compile_designator_expression:
 
 	j .Lcompile_designator_expression_end
 
-.Lcompile_designator_expression_saved:
-	li t0, 0x20766d # mv_
-	sw t0, 12(sp)
-	li a0, 3
-	addi a1, sp, 12
-	call _write_s
-
-	lw a0, 16(sp)
-	lw a1, 20(sp)
-	call _write_s
-
-	li t0, 0x0a # \n
-	sw t0, 12(sp)
-	li t0, 0x3061202c # , a0
-	sw t0, 8(sp)
-	li a0, 5
-	addi a1, sp, 8
-	call _write_s
-
-	j .Lcompile_designator_expression_end
-
 .Lcompile_designator_expression_end:
 	# Epilogue.
 	lw ra, 28(sp)