From 3bf7ba988ea14137fff4e893f85cae43ffe634ea Mon Sep 17 00:00:00 2001
From: PleegWat <pleegwat@telfort.nl>
Date: Wed, 2 Sep 2026 21:11:45 +0200
Subject: [PATCH] Initial version of atoi

Functions to convert strings to integers in various bases
---
 stdlib.asm      |   1 +
 strint.asm      | 145 ++++++++++++++++++++++++++++++++++++++++++++++++
 strint_test.asm |  86 ++++++++++++++++++++++++++++
 3 files changed, 232 insertions(+)
 create mode 100644 strint.asm
 create mode 100644 strint_test.asm

diff --git a/stdlib.asm b/stdlib.asm
index 1b352f1..0135382 100644
--- a/stdlib.asm
+++ b/stdlib.asm
@@ -1,2 +1,3 @@
 pub include bit
 pub include imath
+pub include strint
\ No newline at end of file
diff --git a/strint.asm b/strint.asm
new file mode 100644
index 0000000..b8c45ff
--- /dev/null
+++ b/strint.asm
@@ -0,0 +1,145 @@
+; Convert string to integer
+; Arguments:
+; r1 - Pointer to string
+; Result:
+; r1 - Parsed integer
+; r2 - Pointer to first rejected input byte
+; Clobbers:
+; flags
+; r3 - last character read
+pub fn_atoi:
+load_8 r3, [r1]
+cmp r3, 0x30 ; '0'
+jne fn_atoi_dec ; No prefix, parse decimal
+add r1, r1, 1
+load_8 r3, [r1] ; From "boxBOX", or an octal digit
+cmp r3, 0x30 ; '0'
+jl atoi_badprefix
+cmp r3, 0x37 ; '7'
+jle fn_atoi_oct
+add r1, r1, 1 ; Not octal; 2-byte prefix 
+and r3, r3, 0x5f ; to uppercase
+cmp r3, 0x42 ; 'B'
+je fn_atoi_bin
+cmp r3, 0x4F ; 'O'
+je fn_atoi_oct
+cmp r3, 0x58 ; 'X'
+je fn_atoi_hex
+
+; not a valid prefix, but we did see a zero
+atoi_badprefix:
+mov r2, r1
+mov r1, 0
+; Only exists because conditional register jumps are not allowed
+atoi_done:
+jmp r13
+
+; Convert decimal string to integer
+; Arguments:
+; r1 - Pointer to string
+; Result:
+; r1 - Parsed integer
+; r2 - Pointer to first rejected input byte
+; Clobbers:
+; flags
+; r3 - last character read
+pub fn_atoi_dec:
+mov r2, r1
+mov r1, 0
+atoi_dec_loop:
+load_8 r3, [r2]
+cmp r3, 0x30 ; '0'
+jl atoi_done
+cmp r3, 0x39 ; '9'
+jg atoi_done
+add r2, r2, 1
+sub r3, r3, 0x30 ; '0'
+lsl flags, r1, 2
+add r1, r1, flags
+lsl r1, r1, 1
+add r1, r1, r3
+jmp atoi_dec_loop
+
+; Convert binary string to integer
+; Arguments:
+; r1 - Pointer to string
+; Result:
+; r1 - Parsed integer
+; r2 - Pointer to first rejected input byte
+; Clobbers:
+; flags
+; r3 - last character read
+pub fn_atoi_bin:
+mov r2, r1
+mov r1, 0
+atoi_bin_loop:
+load_8 r3, [r2]
+cmp r3, 0x30 ; '0'
+jl atoi_done
+cmp r3, 0x39 ; '1'
+jg atoi_done
+add r2, r2, 1
+sub r3, r3, 0x30 ; '0'
+lsl r1, r1, 1
+add r1, r1, r3
+jmp atoi_bin_loop
+
+; Convert octal string to integer
+; Arguments:
+; r1 - Pointer to string
+; Result:
+; r1 - Parsed integer
+; r2 - Pointer to first rejected input byte
+; Clobbers:
+; flags
+; r3 - last character read
+pub fn_atoi_oct:
+mov r2, r1
+mov r1, 0
+atoi_oct_loop:
+load_8 r3, [r2]
+cmp r3, 0x30 ; '0'
+jl atoi_done
+cmp r3, 0x39 ; '7'
+jg atoi_done
+add r2, r2, 1
+sub r3, r3, 0x30 ; '0'
+lsl r1, r1, 3
+add r1, r1, r3
+jmp atoi_oct_loop
+
+; Convert hexadecimal string to integer
+; Arguments:
+; r1 - Pointer to string
+; Result:
+; r1 - Parsed integer
+; r2 - Pointer to first rejected input byte
+; Clobbers:
+; flags
+; r3 - last character read
+pub fn_atoi_hex:
+mov r2, r1
+mov r1, 0
+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:
+and r3, r3, 0x5f ; to uppercase
+cmp r3, 0x41 ; 'A'
+jl atoi_done
+cmp r3, 0x46 ; 'F'
+jg atoi_done
+add r2, r2, 1
+sub r3, r3, 0x37 ; 'A' - 10
+lsl r1, r1, 4
+add r1, r1, r3
+jmp atoi_hex_loop
\ No newline at end of file
diff --git a/strint_test.asm b/strint_test.asm
new file mode 100644
index 0000000..d6bc854
--- /dev/null
+++ b/strint_test.asm
@@ -0,0 +1,86 @@
+mov r1, 1
+mov r2, test1
+mov r3, test1_end
+mov r13, test1_pass
+jmp atoi_test
+test1_pass:
+
+mov r1, 2
+mov r2, test2
+mov r3, test2_end
+mov r13, test2_pass
+jmp atoi_test
+test2_pass:
+
+mov r1, 3
+mov r2, test3
+mov r3, test3_end
+mov r13, test3_pass
+jmp atoi_test
+test3_pass:
+
+mov r1, 4
+mov r2, test4
+mov r3, test4_end
+mov r13, test4_pass
+jmp atoi_test
+test4_pass:
+
+mov r1, 5
+mov r2, test5
+mov r3, test5_end
+mov r13, test5_pass
+jmp atoi_test
+test5_pass:
+
+success:
+jmp success
+
+; test strint.fn_atoi
+; Arguments:
+; r1 - test number
+; r2 - test data label
+; r3 - test end-of-string label
+; Result:
+; void. Hangs in failure: on failure.
+; Clobbers:
+; r8 - test number
+; r9 - Expected result in r1
+; r10 - Expected result in r2
+; Notes:
+; Depends on fn_atoi not clobbering r8-r10.
+atoi_test:
+mov r8, r1
+load_32 r9, [r2]
+add r1, r2, 4
+mov r10, r3
+push r13
+mov r13, atoi_test_ret
+jmp stdlib.strint.fn_atoi
+atoi_test_ret:
+pop r13
+cmp r1, r9
+jne failure
+cmp r2, r10
+jne failure
+jmp r13
+
+failure:
+jmp failure
+
+test1: U32 0 "0"
+test1_end: "\0"
+
+test2: U32 1 "1"
+test2_end: "\0"
+
+test3: U32 2 "2"
+test3_end: "\0"
+
+test4: U32 42 "42"
+test4_end: "\0"
+
+test5: U32 67 "67"
+test5_end: "lol"
+
+include stdlib