Support named identifiers on the right side

boot/common-boot.s

@@ -3,7 +3,7 @@
 # obtain one at https://mozilla.org/MPL/2.0/.
 
 .global _is_alpha, _is_digit, _is_alnum, _is_upper, _is_lower
-.global _write_out, _read_file, _write_error, _put_char, _printi
+.global _write_s, _read_file, _write_error, _write_c, _write_i, _print_i
 .global _get, _memcmp, _memchr, _memmem, _memcpy
 .global _divide_by_zero_error, _exit, _mmap
 .global _strings_index, _string_equal
@@ -175,16 +175,20 @@ _is_alnum:
 	addi sp, sp, 16
 	ret
 
-.type _write_out, @function
-_write_out:
+# Writes a string to the standard output.
+#
+# Parameters:
+# a0 - Length of the string.
+# a1 - String pointer.
+.type _write_s, @function
+_write_s:
 	# Prologue.
 	addi sp, sp, -8
 	sw ra, 4(sp)
 	sw s0, 0(sp)
 	addi s0, sp, 8
 
-	mv a2, a1
-	mv a1, a0
+	mv a2, a0
 	li a0, STDOUT
 	li a7, SYS_WRITE
 	ecall
@@ -244,53 +248,87 @@ _divide_by_zero_error:
     ecall
     ret
 
-# a0 - Whole number.
+# Writes a number to a string buffer.
+#
+# t0 - Local buffer.
 # t1 - Constant 10.
-# a1 - Local buffer.
 # t2 - Current character.
 # t3 - Whether the number is negative.
-.type printi, @function
-_printi:
-    addi sp, sp, -16
-    sw s0, 0(sp)
-    sw ra, 4(sp)
-    addi s0, sp, 16
-    addi t1, zero, 10
-    addi a1, s0, -1
+#
+# Parameters:
+# a0 - Whole number.
+# a1 - Buffer pointer.
+#
+# Sets a0 to the length of the written number.
+.type _print_i, @function
+_print_i:
+    addi sp, sp, -32
+    sw ra, 28(sp)
+    sw s0, 24(sp)
+    addi s0, sp, 32
 
-    addi t3, zero, 0
-    bge a0, zero, .digit10
-    addi t3, zero, 1
-    sub a0, zero, a0
+    li t1, 10
+    addi t0, s0, -9
 
-.digit10:
+    li t3, 0
+    bgez a0, .Lprint_i_digit10
+    li t3, 1
+    neg a0, a0
+
+.Lprint_i_digit10:
     rem t2, a0, t1
     addi t2, t2, '0'
-    sb t2, 0(a1)
+    sb t2, 0(t0)
     div a0, a0, t1
-    addi a1, a1, -1
-    bne zero, a0, .digit10
+    addi t0, t0, -1
+    bne zero, a0, .Lprint_i_digit10
 
-    beq zero, t3, .write_call
+    beq zero, t3, .Lprint_i_write_call
     addi t2, zero, '-'
-    sb t2, 0(a1)
-    addi a1, a1, -1
+    sb t2, 0(t0)
+    addi t0, t0, -1
 
-.write_call:
-    addi a0, zero, 1
-    addi a1, a1, 1
-    sub a2, s0, a1
-    addi a7, zero, 64 # write
-    ecall
+.Lprint_i_write_call:
+	mv a0, a1
+	addi a1, t0, 1
+    sub a2, s0, t0
+	addi a2, a2, -9
+	sw a2, 0(sp)
 
-    lw s0, 0(sp)
-    lw ra, 4(sp)
-    addi sp, sp, 16
+	call _memcpy
+
+	lw a0, 0(sp)
+
+    lw ra, 28(sp)
+    lw s0, 24(sp)
+    addi sp, sp, 32
+    ret
+
+# Writes a number to the standard output.
+#
+# Parameters:
+# a0 - Whole number.
+.type _write_i, @function
+_write_i:
+    addi sp, sp, -32
+    sw ra, 28(sp)
+    sw s0, 24(sp)
+    addi s0, sp, 32
+
+	addi a1, sp, 0
+	call _print_i
+
+	addi a1, sp, 0
+	call _write_s
+
+    lw ra, 28(sp)
+    lw s0, 24(sp)
+    addi sp, sp, 32
     ret
 
 # Writes a character from a0 into the standard output.
-.type _put_char, @function
-_put_char:
+.type _write_c, @function
+_write_c:
 	# Prologue
 	addi sp, sp, -16
 	sw ra, 12(sp)