forked from TCShenanigans/symphony_stdlib
62 lines
1.2 KiB
NASM
62 lines
1.2 KiB
NASM
pub mul_low:
|
|
mov r3, 0 ; result
|
|
mov r4, 31 ; loop counter
|
|
|
|
mull_loop:
|
|
asr r5, r2, 31
|
|
and r5, r5, r1
|
|
lsl r5, r5, r4
|
|
add r3, r3, r5
|
|
lsl r2, r2, 1
|
|
sub r4, r4, 1
|
|
cmp r4, 0
|
|
jge mull_loop
|
|
mov r1, r3
|
|
|
|
jmp r13
|
|
|
|
; Calculates the absolute value of the value provided in the r1 register
|
|
; Based on Stanford's BitHacks
|
|
; Clobbers r2
|
|
pub abs: ; SHOULD BE INLINED
|
|
; mask = v >> 31
|
|
asr r2, r1, 31
|
|
; v + mask
|
|
add r1, r1, r2
|
|
; return (v + mask) ^ mask
|
|
xor r1, r1, r2
|
|
jmp r13
|
|
|
|
; Calculates the minimum value of the two values provided in the r1 and r2 registers
|
|
; Based on Stanford's BitHacks
|
|
; Clobbers flags
|
|
pub min: ; SHOULD BE INLINED
|
|
; x < y
|
|
cmp r1, r2
|
|
lsr flags, flags, 2
|
|
; -(x < y)
|
|
neg flags, flags
|
|
; x ^ y
|
|
xor r1, r1, r2
|
|
; (x ^ y) & -(x < y)
|
|
and r1, r1, flags
|
|
; return y ^ ((x ^ y) & -(x < y))
|
|
xor r1, r2, r1
|
|
jmp r13
|
|
|
|
; Calculates the maximum value of the two values provided in the r1 and r2 registers
|
|
; Based on Stanford's BitHacks
|
|
; Clobbers r2 and flags
|
|
pub max: ; SHOULD BE INLINED
|
|
; x < y
|
|
cmp r1, r2
|
|
lsr flags, flags, 2
|
|
; -(x < y)
|
|
neg flags, flags
|
|
; x ^ y
|
|
xor r2, r1, r2
|
|
; (x ^ y) & -(x < y)
|
|
and r2, r2, flags
|
|
; return x ^ ((x ^ y) & -(x < y))
|
|
xor r1, r1, r2
|
|
jmp r13 |