When it was launched, in October 1977, VAX supported only the "D" double-precision floating-point format, which was the same as in the previous DEC computers, like PDP-11, and which had a too small exponent range.
In 1977 there was the first publication about the Intel floating-point format and the standardization work started soon after that.
The first devices that supported in hardware the Intel FP formats, which were later adopted as IEEE 754, were AMD Am9512 in 1979 (second sourced by Intel as 8232), then Intel 8087 in 1980. (At that time Intel and AMD were frequently partners, only several years later, when Intel began to gain tons of money from the IBM PC, they no longer wanted to share that money with anyone, so they severed the links with AMD)
Meanwhile the debates about the future standard continued and DEC acknowledged that their "D" format had a too small exponent range, so they introduced the "G" format in VAX, which was similar, but not identical (different exponent bias) with the format proposed by Intel.
In 1978 DEC VAX did not have the "G" format and in 1982 it had the "G" format, so it was introduced between 1979 and 1981, possibly at about the same time as Intel 8087, but in any case it was not completely compliant with the proposed standard and DEC still hoped that they might succeed to impose their own FP formats.
