[0] Perl> printf "dp:%u : %.*f\n", $_, $_, 123e-308 for 300 .. 320;;
dp:300 : 0.000 {300 zeros ellided} 000000000000
dp:301 : 0.000 {300 zeros ellided} 0000000000000
dp:302 : 0.000 {300 zeros ellided} 00000000000000
dp:303 : 0.000 {300 zeros ellided} 000000000000000
dp:304 : 0.000 {300 zeros ellided} 0000000000000000
dp:305 : 0.000 {300 zeros ellided} 00000000000000000
dp:306 : 0.000 {300 zeros ellided} 000000000000000001
dp:307 : 0.000 {300 zeros ellided} 0000000000000000012
dp:308 : 0.000 {300 zeros ellided} 00000000000000000123
dp:309 : 0.000 {300 zeros ellided} 000000000000000001230
dp:310 : 0.000 {300 zeros ellided} 0000000000000000012300
dp:311 : 0.000 {300 zeros ellided} 00000000000000000123000
dp:312 : 0.000 {300 zeros ellided} 000000000000000001230000
dp:313 : 0.000 {300 zeros ellided} 0000000000000000012300000
dp:314 : 0.000 {300 zeros ellided} 00000000000000000123000000
dp:315 : 0.000 {300 zeros ellided} 000000000000000001230000000
dp:316 : 0.000 {300 zeros ellided} 0000000000000000012300000000
dp:317 : 0.000 {300 zeros ellided} 00000000000000000123000000000
dp:318 : 0.000 {300 zeros ellided} 000000000000000001230000000000
dp:319 : 0.000 {300 zeros ellided} 0000000000000000012300000000000
dp:320 : 0.000 {300 zeros ellided} 00000000000000000123000000000000