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author | Aqua-sama <aqua@iserlohn-fortress.net> | 2021-02-11 16:17:53 +0200 |
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committer | Aqua-sama <aqua@iserlohn-fortress.net> | 2021-02-11 21:33:21 +0200 |
commit | 9a299f2fe91554a1b9d9db402391ae757c591ef8 (patch) | |
tree | 2ec839c869316804954e6b09220140346874aa8d /drivers/ports.h | |
parent | Generate target dependency files (diff) | |
download | kernel.cpp-9a299f2fe91554a1b9d9db402391ae757c591ef8.tar.xz |
Add comments to explain CGA ports better
Diffstat (limited to 'drivers/ports.h')
-rw-r--r-- | drivers/ports.h | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/drivers/ports.h b/drivers/ports.h new file mode 100644 index 0000000..338c3b8 --- /dev/null +++ b/drivers/ports.h @@ -0,0 +1,47 @@ +#pragma once + +template <typename T> +concept port_data_t = (is_same<T, uint8_t>::value || is_same<T, uint16_t>::value || is_same<T, uint32_t>::value); + +template <uint16_t port_num, port_data_t T> +class Port { +public: + [[nodiscard]] T read() { + T result; + + switch (sizeof(T)) { + case 1: + asm volatile("inb %1, %0" : "=a"(result) : "Nd"(port_num)); + break; + case 2: + asm volatile("inw %1, %0" : "=a"(result) : "Nd"(port_num)); + break; + case 4: + asm volatile("inl %1, %0" : "=a"(result) : "Nd"(port_num)); + break; + } + + return result; + } + + void write(T data) { + switch (sizeof(T)) { + case 1: + asm volatile("outb %0, %1" : : "a"(data), "Nd"(port_num)); + break; + case 2: + asm volatile("outw %0, %1" : : "a"(data), "Nd"(port_num)); + break; + case 4: + asm volatile("outl %0, %1" : : "a"(data), "Nd"(port_num)); + break; + } + } +}; + +/* Ports 0x3d0 to 0x3df are reserved for CGA; each port is 1 byte wide */ +typedef Port<0x3d4, uint8_t> cga_idx_port; +typedef Port<0x3d5, uint8_t> cga_dat_port; +// 0x3d8 : mode select register +// 0x3d8 : color control register +// 0x3da : status register |