1 files changed, 19 insertions, 0 deletions
diff --git a/readme.md b/readme.md
index a9fa679..a4aaad5 100644
--- a/readme.md
+++ b/readme.md
@@ -118,6 +118,25 @@ a variable containing a boolean value.
 if 0 (false), the system is in interpreting mode,
 if -1 (true), the system is in compiling mode.
 
+### `syscall0   ( rax -- u )`
+perform the syscall with the id in `rax`,
+and push the value of the `rax` register to the stack.
+
+### `syscall1   ( rdi rax -- u )`
+perform the syscall with the id in `rax`,
+taking one parameter placed in `rdi`,
+and push the value of the `rax` register to the stack.
+
+### `syscall2   ( rsi rdi rax -- u )`
+perform the syscall with the id in `rax`,
+taking two parameters placed in `rdi` and `rsi`,
+and push the value of the `rax` register to the stack.
+
+### `syscall3   ( rdx rsi rdi rax -- u )`
+perform the syscall with the id in `rax`,
+taking three parameters placed in `rdi`, `rsi` and `rdx`,
+and push the value of the `rax` register to the stack.
+
 ### `tib   ( -- a )`
 a variable containing the address of the current input buffer.