wtf is sdcc doing
```
                                    943 ;	main.c:261: desc_string = (__xdata char *)usb_strings[usb_device.iProduct - 1];
      000192 90r00r0F         [24]  944 	mov	dptr,#(_usb_device + 0x000f)
      000195 E4               [12]  945 	clr	a
      000196 93               [24]  946 	movc	a,@a+dptr
      000197 FF               [12]  947 	mov	r7,a
      000198 1F               [12]  948 	dec	r7
      000199 C2 D5            [12]  949 	clr	F0
      00019B 75 F0 02         [24]  950 	mov	b,#0x02
      00019E EF               [12]  951 	mov	a,r7
      00019F 30 E7 04         [24]  952 	jnb	acc.7,00130$
      0001A2 B2 D5            [12]  953 	cpl	F0
      0001A4 F4               [12]  954 	cpl	a
      0001A5 04               [12]  955 	inc	a
      0001A6                        956 00130$:
      0001A6 A4               [48]  957 	mul	ab
      0001A7 30 D5 0A         [24]  958 	jnb	F0,00131$
      0001AA F4               [12]  959 	cpl	a
      0001AB 24 01            [12]  960 	add	a,#0x01
      0001AD C5 F0            [12]  961 	xch	a,b
      0001AF F4               [12]  962 	cpl	a
      0001B0 34 00            [12]  963 	addc	a,#0x00
      0001B2 C5 F0            [12]  964 	xch	a,b
      0001B4                        965 00131$:
      0001B4 24r97            [12]  966 	add	a,#_usb_strings
      0001B6 F5 82            [12]  967 	mov	dpl,a
      0001B8 74s00            [12]  968 	mov	a,#(_usb_strings >> 8)
      0001BA 35 F0            [12]  969 	addc	a,b
      0001BC F5 83            [12]  970 	mov	dph,a
      0001BE E4               [12]  971 	clr	a
      0001BF 93               [24]  972 	movc	a,@a+dptr
      0001C0 FE               [12]  973 	mov	r6,a
      0001C1 A3               [24]  974 	inc	dptr
      0001C2 E4               [12]  975 	clr	a
      0001C3 93               [24]  976 	movc	a,@a+dptr
      0001C4 FF               [12]  977 	mov	r7,a