作者gR7P4zXH (tpn7gpdx)
看板DigiCurrency
标题[发钱] BTC
时间Sat Oct 19 00:01:30 2019
在 8 位元 Motorola 6809 处理器上，有道指令叫做 SEX，寓意是 “Sign EXtend”
SEX 123 应该输出 0, 而 SEX -3 要输出 0xffffffff (取决於有效位数)
考虑一个 32 位元版本的 SEX 实作如下，假设执行环境是 little-endian:
#include <stdint.h>
static inline uint32_t sex32(int32_t x) {
union {
TYPE w;
struct { uint32_t lo, hi; };
} z = {.w = x};
return z.hi;
}
试问: TYPE=?
第一个留下正确答案和地址的推文赠20000 satoshi
Answer:
uint64_t或int64_t
lilian0111 & akuei1031 各解出一半，得 10000 satashi
TXID
b153cdf0174f82ec9b7f0eb699e814f4d6b565dbfbb936cbbdb971dd34ebec00
--
※ 发信站: 批踢踢实业坊(ptt.cc), 来自: 118.168.121.100 (台湾)
※ 文章网址: https://webptt.com/cn.aspx?n=bbs/DigiCurrency/M.1571414492.A.61F.html
1F：推 roger: int32_t 10/19 00:07
2F：→ roger: 1DuB4FPbqQPLAMDVuBjxFRgSGwRo4uN8DB 10/19 00:07
3F：推 TimWater: 等下大家都在出题发钱了吗xd 10/19 00:56
--------------------
4F：推 lilian0111: int64_t 10/19 01:34
5F：→ lilian0111: 3LuUjqSZuvBrxH53L2nVPhvVfk5n57cXyt 10/19 01:34
--------------------
6F：推 k3588140: int_64t 10/19 08:06
7F：→ k3588140: 1Cpqc6M49mMy3krhrQzv4SWcRH2otQFesD 10/19 08:06
8F：推 george126: int_32t 10/19 09:33
9F：→ george126: 39Hhc4uAG3HDSJz2cEGsQweSUEfciRrG7Y 10/19 09:33
10F：→ dennisxkimo: int32_t 1FsQ8UnHsYAfzutCKTkt6tLAzsWmoEkqeW 10/19 10:35
--------------------
11F：→ akuei1031: uint64_t 10/19 12:18
12F：→ akuei1031: 3QX6ZiHxT6o5r6DEKnsFUXsMBWAUDUwTrU 10/19 12:19
--------------------
13F：推 SRNOB: format c: 10/20 01:12
14F：推 mongala: int64_t 10/20 01:12
15F：→ mongala: 1EHtAaiS6EMR3oFnHHeTarmc97fq9A8tio 10/20 01:12
16F：推 AppMaker: uint32_t 10/20 05:48
17F：推 akuei1031: uint64_t 10/20 23:09
18F：→ akuei1031: 3QX6ZiHxT6o5r6DEKnsFUXsMBWAUDUwTrU 10/20 23:10
19F：推 akuei1031: 突然发现前几天按错没推到赶快补推QQ 10/20 23:11
20F：推 dennisxkimo: int32_t 1FsQ8UnHsYAfzutCKTkt6tLAzsWmoEkqeW 10/20 23:34
21F：推 AcousticLove: int32_t 3LX8YG2TE2bjuBSaoU7Npd9dTi1RtxZx5g 10/22 06:56
※ 编辑: gR7P4zXH (140.115.52.18 台湾), 10/24/2019 01:25:17
22F：→ akuei1031: 感谢老板 10/24 12:31