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kvisc/ka/crt/fmt/ltostr.k
julianb0 89ed8fdc0d
vm
2019-08-03 17:41:44 +02:00

84 lines
1.3 KiB
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; The OS/K Team licenses this file to you under the MIT license.
; See the LICENSE file in the project root for more information.
;
; void itoa(char *buf, int num, int base)
;
itoa:
mov ax3, 1
jmp ltostr
;
; void utoa(char *buf, int num, int base)
;
utoa:
mov ax3, zero
jmp ltostr
;
; void ltostr(char *buf, int num, int base, bool signed)
;
ltostr:
mov rax, ax0
; make sure base is in [2, 32]
b.b ax2, 2, .bad
b.a ax2, 36, .bad
; deal with zero
b.z ax1, zero, .is_zero
; deal with base 10 signedness
b.z ax3, zero, .conv
b.nz ax2, 10, .conv ; base 10
shr rcx, ax1, 63 ; extract ax1 sign
sub.cxnz ax1, zero, ax1 ; NEG if negative
; main loop
.conv:
b.z ax1, zero, .fini
rem rdx, ax1, ax2 ; ax1 % base
b.a rdx, 9, .nondec ; rdx > 9 ?
inc rdx, '0'
jmp .next
.nondec:
inc rdx, 55 ; 'A' - 10
.next:
mov b[ax0], rdx
inc ax0, 1
div ax1, ax1, ax2
jmp .conv
; add minus flag, null-terminate and reverse
.fini:
mov.cxnz b[ax0], '-'
add.cxnz ax0, ax0, 1
mov b[ax0], zero
call strrev2, rax
ret
;
; exceptional cases
;
.bad:
mov q[errno], EINVAL
mov b[ax0], 0
ret
.is_zero:
mov b[ax0], 48 ; '0'
mov b[ax0+1], 0
ret