littlebigcomputer/programs/parva/pythagorean_triples_2.lbpasm
2023-10-30 17:50:05 +01:00

273 lines
4.9 KiB
Text

; calculate all primitive pythogorean triples (a^2 + b^2 = c^2) where c <= 32
.eq limit 32
li sp, stack
li x0, 1
sw x0, cursor_x
sw x0, cursor_y
sw x0, gpu_clear_screen(upper)
# main stack frame:
# sp-(limit + 2): table
# sp-2: a
# sp-1: a^2
main:
li x7, limit # limit
mv x6, sp # x6 = table base
add sp, sp, x7
addi sp, sp, 2 # reserve rest of stack frame
# --- zero-fill table ---
mv x5, x6
li x2, 0
.align 2
main__clear_table:
sw x2, 0(x5)
addi x5, x5, 1
ble x5, sp, main__clear_table
# --- calculate primes factors ---
li x0, 1 # x0 = prime
li x2, 1 # x2 = prime factor bit
main__primes:
addi x0, x0, 1
bgt x0, x7, main__primes_end
add x4, x6, x0
lw x4, 0(x4)
bnez x4, main__primes
mv x3, x0 # x3 = multiple
main__multiples:
add x5, x6, x3
lw x4, 0(x5) # x4 = current prime factor bits
or x4, x4, x2 # x4 |= add current prime factor bit
sw x4, 0(x5)
add x3, x3, x0
ble x3, x7, main__multiples
slli x2, x2, 1 # update prime bit
b main__primes
main__primes_end:
# --- find pythagorean triples ---
li x0, 1 # a = 1
main__iterate_a:
lw x0, -2(sp)
addi x0, x0, 1 # x0 = a
sw x0, -2(sp)
bge x0, x7, main__end
mulu x2, x0, x0 # x2 = a^2
sw x2, -1(sp)
add x3, x6, x0
lw x3, 0(x3) # x3 = a prime factors
mv x4, x0 # x4 = b
main__iterate_b:
addi x4, x4, 1
bgt x4, x7, main__iterate_a
add x5, x6, x4
lw x5, 0(x5) # x5 = b prime factors
and x5, x5, x3
bnez x5, main__iterate_b # check if a and b are coprime
mulu x5, x4, x4
lw x0, -1(sp) # x0 = a^2
add x5, x5, x0 # x5 = a^2 + b^2
mv x0, x4 # x0 = c
addi x2, x0, 1
mulu x2, x2, x2
bgt x2, x5, main__iterate_a
main__iterate_c:
addi x0, x0, 1 ; c += 1
mulu x2, x0, x0 # x2 = c^2
bgt x2, x5, main__iterate_b
bne x2, x5, main__iterate_c
# found triple
push x6
push x7
push x0
push x4
lw a0, -6(sp)
call print_number
lw x6, cursor_x
addi x6, x6, 4
sw x6, cursor_x
pop a0
call print_number
lw x6, cursor_x
addi x6, x6, 4
sw x6, cursor_x
pop a0
call print_number
# newline
li x6, 1
sw x6, cursor_x
lw x7, cursor_y
addi x7, x7, 6
sw x7, cursor_y
pop x7
pop x6
b main__iterate_a
main__end:
wfi
# end main()
.eq gpu_clear_screen 0b01_0100_000000
.eq gpu_move_cursor 0b01_0000_000000
.eq gpu_print_char 0b01_0010_000000
.eq gpu_show_buffer 0b01_0011_000000
cursor_x:
.data 1
cursor_y:
.data 1
# void print_number(*void return: ra, int number: a0)
print_number:
push ra
mv x0, a0
li x2, 0
.align 2
# https://ridiculousfish.com/blog/posts/labor-of-division-episode-i.html
print_number__bin_to_dec_loop:
lw x4, print_number__ten_powers(x2)
beqz x4, print_number__end_bin_to_dec_loop
slli x5, x2, 1
lw x3, print_number__ten_divisors(x5)
mulhu x6, x0, x3
sub x7, x0, x6
srli x7, x7, 1
lw x5, (print_number__ten_divisors + 1)(x5)
add x3, x7, x6
srl x3, x3, x5 # x3 = digit of result
sw x3, print_number__result_string(x2)
mulu x3, x3, x4
sub x0, x0, x3
addi x2, x2, 1
b print_number__bin_to_dec_loop
print_number__end_bin_to_dec_loop:
sw x0, print_number__result_string(x2)
li x0, -1
lw x6, cursor_x
lw x7, cursor_y
print_number__skip_zeroes:
addi x0, x0, 1
lw x4, print_number__result_string(x0)
beqz x4, print_number__skip_zeroes
print_number__print_loop:
sd x67, gpu_move_cursor(upper)
nop
nop
nop # give time for the cursor to move
lw x4, print_number__result_string(x0)
bltz x4, print_number__end_print_loop
slli x4, x4, 1
lw x2, print_number__char_pixels(x4)
lw x3, (print_number__char_pixels + 1)(x4)
addi x6, x6, 4
addi x0, x0, 1
sd x23, gpu_print_char(upper)
b print_number__print_loop
print_number__end_print_loop:
sd x01, gpu_show_buffer(upper) # gpu show buffer
sw x6, cursor_x
pop ra
j ra
print_number__ten_powers:
.data 10000000
.data 1000000
.data 100000
.data 10000
.data 1000
.data 100
.data 10
.data 0
print_number__ten_divisors:
.data 0xad7f2a 23 # 10000000
.data 0x0c6f7b 19 # 1000000
.data 0x4f8b59 16 # 100000
.data 0xa36e2f 13 # 10000
.data 0x0624de 9 # 1000
.data 0x47ae15 6 # 100
.data 0x99999a 3 # 10
print_number__char_pixels:
.data 0b111000_101000_101000_101000 # 0
.data 0b111000_000000_000000_000000
.data 0b001000_001000_001000_001000 # 1
.data 0b001000_000000_000000_000000
.data 0b111000_001000_111000_100000 # 2
.data 0b111000_000000_000000_000000
.data 0b111000_001000_111000_001000 # 3
.data 0b111000_000000_000000_000000
.data 0b101000_101000_111000_001000 # 4
.data 0b001000_000000_000000_000000
.data 0b111000_100000_111000_001000 # 5
.data 0b111000_000000_000000_000000
.data 0b111000_100000_111000_101000 # 6
.data 0b111000_000000_000000_000000
.data 0b111000_001000_001000_010000 # 7
.data 0b010000_000000_000000_000000
.data 0b111000_101000_111000_101000 # 8
.data 0b111000_000000_000000_000000
.data 0b111000_101000_111000_001000 # 9
.data 0b001000_000000_000000_000000
print_number__result_string:
.repeat 0 8
.data -1
# end print_number()
.align 2
stack:
.data 0