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ZERICO2005ZERICO2005
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implemented strto(u)l in assembly
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6 files changed

+724
-116
lines changed

6 files changed

+724
-116
lines changed

‎src/libc/strtol.c‎

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This file was deleted.

‎src/libc/strtol.src‎

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assume adl=1
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;-------------------------------------------------------------------------------
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section .text
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public _strtol
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_strtol:
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call __strtol_common
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; overflow occured if B is non-zero
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djnz .out_of_range
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ld a, e
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rla
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jr c, .maybe_out_of_range
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ret nz
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jp __lneg
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.maybe_out_of_range:
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; greater than INT_MAX
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jr nz, .overflow
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; negative
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; check that the result is not an exact INT_MIN
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or a, a
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adc hl, hl
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jr nz, .underflow
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ld a, e
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adc a, a
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ret z ; exact INT_MIN
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.underflow:
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xor a, a ; set Z
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.out_of_range:
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.overflow:
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ld e, $80
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ld hl, 5 ; ERANGE
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ld (_errno), hl
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ld l, h ; ld hl, 0
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ret z ; underflow
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; overflow
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dec hl
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dec e
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ret
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;-------------------------------------------------------------------------------
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section .text
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public _strtoul
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_strtoul:
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call __strtol_common
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; overflow occured if B is non-zero
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djnz .out_of_range
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ret nz
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jp __lneg
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.out_of_range:
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ld hl, 5 ; ERANGE
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ld (_errno), hl
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ld l, h ; ld hl, 0
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dec hl
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ld e, l
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ret
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;-------------------------------------------------------------------------------
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section .text
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private __strtol_common
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__strtol_common:
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; output: E:UHL
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; B = 1 if no overflow
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; Z means that A is zero = negate return value
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; NZ means that A is non-zero = positive return value
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push ix
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ld ix, 0
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lea hl, ix - 37 ; ld hl, -37
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add ix, sp
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ld bc, (ix + 15) ; base
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add hl, bc
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jr c, .invalid_base
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; UBC is zero here
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ld b, c ; store the base in B to allow for djnz hax
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ld hl, (ix + 9) ; nptr
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;-------------------------------------------------------------------------------
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; consume whitespace (inlinsed isspace)
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.whitespace_loop:
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ld a, (hl)
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inc hl
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cp a, 32
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jr z, .whitespace_loop
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sub a, 9
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add a, -5
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jr nc, .whitespace_loop
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; test for plus/minus signs
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; A = (HL - 1) - 9 + -5
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; A = (HL - 1) - 14
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xor a, '-' - 14
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push af
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jr z, .minus_sign
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xor a, ('+' - 14) xor ('-' - 14)
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jr z, .plus_sign
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dec hl
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xor a, a
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.plus_sign:
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.minus_sign:
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; A = 0, (HL) = start of number
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;-------------------------------------------------------------------------------
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; update the base if needed
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or a, b ; base
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jr z, .auto_base
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xor a, 16
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jr z, .hex_base
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xor a, 2 xor 16
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jr nz, .other_base
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.auto_base: ; test for 0* 0x* 0X* 0b* 0B*
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.bin_base: ; test for 0x* 0X*
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.hex_base: ; test for 0b* 0B*
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inc b ; djnz hax
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ld a, (hl)
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xor a, '0'
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jr nz, .maybe_decimal
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inc hl
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ld a, (hl)
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res 5, a ; upper case
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xor a, 'X'
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jr z, .maybe_hex
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xor a, 'B' xor 'X'
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jr z, .maybe_bin
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dec hl
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djnz .other_base
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ld b, 8 ; octal
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jr .save_new_base
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.maybe_bin:
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bit 4, b
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jr nz, .undo_inc ; hexadecimal
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; base is 0 or 2
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inc hl
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ld b, 2
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jr .save_new_base
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.maybe_hex:
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bit 1, b
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jr nz, .undo_inc ; binary
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; base is 0 or 16
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inc hl
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ld b, 16
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jr .save_new_base
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.undo_inc:
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dec hl
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; dec b
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; jr .other_base
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.maybe_decimal:
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; set to decimal if base is not zero
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djnz .other_base
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ld b, 10 ; decimal
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.save_new_base:
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;-------------------------------------------------------------------------------
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.other_base:
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ld a, (hl) ; first digit of the number
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push hl
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pop iy
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ld d, b
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.invalid_base_hijack:
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; or a, a ; carry is cleared here
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sbc hl, hl
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ld e, l
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ld b, l
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; A = first digit of the number
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; E:UHL = 0
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; D = base
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; UBC = 0 when base is valid (otherwise unknown)
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; B = 0
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; The strto* functions return nptr (not nptr + whitespace) if there are
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; no digits in the string. Having a digit check here allows us to
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; directly handle the case where the string has no digits.
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sub a, 48
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cp a, 10
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jr c, .check_digit
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; Convert an alphabetic digit, case-insensitive
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sub a, 65 - 48
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res 5, a
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add a, 10
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.check_digit:
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; End the loop when the digit is out of range for the base
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cp a, d
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jr c, .loop
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;-------------------------------------------------------------------------------
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; no digit found or invalid base
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; set *endptr to nptr and return 0
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ld iy, (ix + 9) ; nptr
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jr .write_endptr
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.invalid_base:
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xor a, a
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ld d, a
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; Setting D (base) to zero ensures that cp a, d will never set carry.
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; forcing the function to return.
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push af
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; sets E:UHL to zero
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jr .invalid_base_hijack
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;-------------------------------------------------------------------------------
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; common path : 30F + 1R + 3W + 5 + __lmulu_b
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; decimal path : 6F + 0R + 0W + 1
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; other path : 12F + 0R + 0W + 1
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;
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; decimal digit : 36F + 1R + 3W + 4 + __lmulu_b
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; other digit : 42F + 1R + 3W + 4 + __lmulu_b
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; __lmulu_b : 43F + 12R + 9W + 17
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;
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; Total CC per digit:
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; decimal digit : 79F + 13R + 12W + 21
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; other digit : 85F + 13R + 12W + 21
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.check_decimal:
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cp a, d
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jr nc, .end_loop
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.loop:
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ld c, a ; UBC = digit if no carry, don't care otherwise
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ld a, d ; A = base
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ld d, e ; D = upper accumulator byte
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ld e, b ; E = 0 if no carry, don't care otherwise
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; E:UHL = UHL * base
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call __lmulu_b
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; Add digit to lower product bytes
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add hl, bc
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ld c, a ; C = base
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ld a, e ; A = upper product byte
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ld e, c ; E = base
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mlt de ; DE = upper accumulator byte * base
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; Carry into upper product byte
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adc a, e
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ld e, a
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; Set B != 0 if any carry from the upper byte or previous iterations
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sbc a, a
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or a, d
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or a, b
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ld b, a
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ld d, c ; D = base
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; IY = str, D = base, E:UHL = accumulator, BCU = 0, B = 0 if no carry
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.next_digit:
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inc iy
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; Convert a numerical digit
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ld a, (iy)
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sub a, 48
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cp a, 10
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jr c, .check_decimal
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; Convert an alphabetic digit, case-insensitive
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sub a, 65 - 48
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res 5, a
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add a, 10
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; End the loop when the digit is out of range for the base
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cp a, d
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jr c, .loop
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.end_loop:
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;-------------------------------------------------------------------------------
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.write_endptr:
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push hl
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ld hl, (ix + 12) ; endptr
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add hl, de
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or a, a
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sbc hl, de
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jr z, .endptr_null
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ld (hl), iy
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.endptr_null:
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pop hl
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inc b ; djnz hax
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pop af
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pop ix
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ret
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extern _errno
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extern __lneg
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extern __lmulu_b

‎src/libc/strtoul.c‎

Lines changed: 0 additions & 8 deletions
This file was deleted.

‎src/libc/strtoull.c‎

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#define STRTOX_TYPE long long
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#define STRTOX_MAX ULLONG_MAX
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#define STRTOX_MIN 0
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#define STRTOX_MIN ULLONG_MAX
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#define STRTOX_SIGNED 0
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#define STRTOX_NAME strtoull

‎test/standalone/atol/src/char_to_digit.asm‎

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assume adl=1
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section .text
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public _char_to_digit
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; char char_to_digit(char c)
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_char_to_digit:
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; returns [0, 9] when ['0', '9']
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; returns [10, 35] when ['A', 'Z'] or ['a', 'z']
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; otherwise returns -1
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ld iy, 3
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add iy, sp
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;-------------------------------------------------------------------------------
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ld a, (iy)
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sub a, 48
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cp a, 10
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jr c, .check_digit
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; Convert an alphabetic digit, case-insensitive
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sub a, 65 - 48
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res 5, a
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add a, 10
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.check_digit:
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cp a, 36
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ret c
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ld a, -1
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ret

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