[syntax] u64(a), u64:8(a), u64:(U0_argv, I_2, 8)

[iacore]

What are those?

mir/mir-tests/test15.mir

Line 6 in 928e28f

add i64:8(a), i64:8(a), 18

u64:(U0_argv, I_2, 8) is in the code below

M0:	module
proto0:	proto	i32, u64:U0___s
	import	puts
main:	func	i32, i32:i0_argc, u64:U0_argv
	local	i64:i1_i, i64:i_0, i64:i_1, i64:I_2, i64:i_3, i64:i_4, i64:i_5
# 2 args, 7 locals
	mov	i1_i, 0
	bges	L3, i1_i, i0_argc
L1:
	ext32	I_2, i1_i
	call	proto0, puts, i_1, u64:(U0_argv, I_2, 8)
L2:
	mov	i_3, i1_i
	adds	i_3, i_3, 1
	mov	i1_i, i_3
	blts	L1, i1_i, i0_argc
L3:
	ret	0
	endfunc
	export	main
	endmodule

[vnmakarov]

u64:(U0_argv, I_2, 8) is

uint64 value in memory whose address is U0_argv + I_2 * 8. It is an address where base and index regs are used (the constant displacement is zero). The uint64 value is passed as the first arg of puts call. It seems the code is a modified version of mir-code generated by c2m.

[iacore]

I don't see this feature documented. Is this the preferred way to do memory access in MIR?

[vnmakarov]

It is documented:

mir/MIR.md

Lines 201 to 207 in 8f04165

	* Memory operand has the following syntax in MIR text (absent displacement means zero one,
	absent scale means one, scale should be 1, 2, 4, or 8):
	```
	<type>: <disp>
	<type>: [<disp>] (<base reg> [, <index reg> [, <scale> ]])
	```