From 39681790260f6e9d62cd5f177d4ff8d629d0646b Mon Sep 17 00:00:00 2001
From: PleegWat <pleegwat@telfort.nl>
Date: Fri, 4 Sep 2026 23:07:21 +0200
Subject: [PATCH] Optimize digit parse loops

---
 strint.asm      | 50 ++++++++++++++++++-------------------------------
 strint_test.asm |  6 +++---
 2 files changed, 21 insertions(+), 35 deletions(-)

diff --git a/strint.asm b/strint.asm
index a807bf2..752b74f 100644
--- a/strint.asm
+++ b/strint.asm
@@ -66,12 +66,10 @@ add r2, r2, 1
 atoi_dec_loop:
 load_8 r3, [r2]
 atoi_dec_positive:
-cmp r3, 0x30 ; '0'
-jl atoi_done
-cmp r3, 0x39 ; '9'
-jg atoi_done
-add r2, r2, 1
 sub r3, r3, 0x30 ; '0'
+cmp r3, 9
+ja atoi_done
+add r2, r2, 1
 lsl flags, r1, 2        ; Use flags to help multiply by 10
 add r1, r1, flags
 lsl r1, r1, 1
@@ -105,12 +103,10 @@ jne atoi_bin_loop
 add r2, r2, 2
 atoi_bin_loop:
 load_8 r3, [r2]
-cmp r3, 0x30 ; '0'
-jl atoi_done
-cmp r3, 0x31 ; '1'
-jg atoi_done
-add r2, r2, 1
 sub r3, r3, 0x30 ; '0'
+cmp r3, 1
+ja atoi_done
+add r2, r2, 1
 lsl r1, r1, 1
 add r1, r1, r3
 jmp atoi_bin_loop
@@ -142,12 +138,10 @@ jne atoi_oct_loop
 add r2, r2, 2
 atoi_oct_loop:
 load_8 r3, [r2]
-cmp r3, 0x30 ; '0'
-jl atoi_done
-cmp r3, 0x37 ; '7'
-jg atoi_done
-add r2, r2, 1
 sub r3, r3, 0x30 ; '0'
+cmp r3, 7
+ja atoi_done
+add r2, r2, 1
 lsl r1, r1, 3
 add r1, r1, r3
 jmp atoi_oct_loop
@@ -175,28 +169,20 @@ atoi_hex_positive:
 load_16 r3, [r2]        ; check for prefix
 or r3, r3, 0x20         ; 2nd char to lower case
 cmp r3, 0x3078 ; "0x"
-jne atoi_oct_loop
+jne atoi_hex_loop
 add r2, r2, 2
 atoi_hex_loop:
 load_8 r3, [r2]
-cmp r3, 0x30 ; '0'
-jl atoi_done
-cmp r3, 0x39 ; '9'
-jg atoi_hex_letter
-add r2, r2, 1
 sub r3, r3, 0x30 ; '0'
-lsl r1, r1, 4
-add r1, r1, r3
-jmp atoi_hex_loop
-
-atoi_hex_letter:
-or r3, r3, 0x20 ; to lower case
-cmp r3, 0x61 ; 'a'
-jl atoi_done
-cmp r3, 0x66 ; 'f'
-jg atoi_done
+cmp r3, 10
+jb atoi_hex_add
+sub r3, r3, 0x11 ; 'A' - '0'
+and r3, r3, 0xdf        ; to lower case
+cmp r3, 5               ; 0-5: 6 letters
+ja atoi_done
+add r3, r3, 10          ; Adjust for digits below
+atoi_hex_add:
 add r2, r2, 1
-sub r3, r3, 0x57 ; 'a' - 10
 lsl r1, r1, 4
 add r1, r1, r3
 jmp atoi_hex_loop
diff --git a/strint_test.asm b/strint_test.asm
index e44c051..9133f3c 100644
--- a/strint_test.asm
+++ b/strint_test.asm
@@ -42,11 +42,11 @@ tests:
 @0x1000 U32 0           U8 0   "\0"
 @0x1010 U32 0           U8 1   "0\0"
 @0x1020 U32 1           U8 1   "1\0"
-@0x1030 U32 2           U8 1   "2\0"
+@0x1030 U32 2           U8 1   "2:\0"
 @0x1040 U32 42          U8 2   "42\0"
 @0x1050 U32 67          U8 2   "67lol\0"
-@0x1060 U32 0x69a       U8 5   "0x69a\0"
-@0x1070 U32 0x4B4       U8 5   "0x4B4\0"
+@0x1060 U32 0x69a       U8 5   "0x69a@\0"
+@0x1070 U32 0x4B4       U8 5   "0x4B4g\0"
 @0x1080 U32 0o23        U8 4   "0o239\0"
 @0x1090 U32 0b1011      U8 6   "0b1011\0"
 @0x10a0 U32 0b10001     U8 7   "0b100012\0"