Add b32d for future decoder implementation, update test

1 files changed, 47 insertions, 0 deletions

diff --git a/b32d.asm b/b32d.asm
new file mode 100644
index 0000000..aa7582b
--- /dev/null
+++ b/b32d.asm
@@ -0,0 +1,47 @@
+section .bss
+
+input_buffer resb 8
+output_buffer resb 8
+
+section .text
+global _start
+
+; read_input
+; reads 5 bytes (40 bits) of input
+; uses reg: rax, rdi, rsi, rdx
+; uses mem: input_buffer
+read_input:
+    ; linux x64 read(stdin, input_buffer, 5)
+    mov rax, 0
+    mov rdi, 0
+    mov rsi, input_buffer
+    mov rdx, 5
+    syscall
+    ret
+
+; write_output
+; writes the output buffer to stdout
+; uses reg: rax, rdi, rsi, rdx
+; uses mem: output_buffer(ro)
+write_output:
+    ; linux x64 write(stdout, output_buffer, 8)
+    mov rax, 1
+    mov rdi, 1
+    mov rsi, output_buffer
+    mov rdx, 8
+    syscall
+    ret
+
+; b32d
+; decodes 8 RFC4648 characters without checking its validity (!!!)
+; uses reg:
+; uses mem: input_buffer, output_buffer
+b32d:
+    ret
+
+_start:
+.exit:
+    ; linux x64 exit(0)
+    mov rax, 60
+    mov rdi, 0
+    syscall