I can save a float into a 32 bit register with the following command:

mov ebx,__?float32?__(1.23)
movd xmm1,ebx  ; works

However when I try the following code, I get an error:

mov bx,__?float16?__(1.23)
movd xmm1,bx   ; /tmp/SASM/program.asm:9: error: invalid combination of opcode and operands

How can I use mov to save a 8.8 float into a 16- bit register? Or is there some other way to do so?

CodePudding user response：

Fixed point values have an implied shift value.

To save an 8.8 fixed point value in a register in NASM you'd have to do the implied shift yourself; like maybe mov ebx,320 ;1.25 << 8 = 320.

Note: Based on this stackoverflow question I don't think there's a way to convert the result of a floating point constant expression into an integer when assembling in NASM, so something cleaner (like a hypothetical mov ebx, __?int32?__ (1.25 << 8)) won't work.